When the Legends realize that they broke the timeline, Rip Hunter arrives with his new organization - the Time Bureau - to relieve them of duty. The Legends are thrilled to get a chance to put the team back together but a new threat arises when Rory spots Julius Caesar in Aruba. Sara, Nate and Ray devise a plan to steal the Waverider back from the Time Bureau in order to try and stop Julius Caesar from conquering the modern world.

The Legends find themselves in 1870 to fix the anachronism which happens to be at P.T. Barnum's fledgling circus. However, Nate and Ray accidentally free a saber toothed tiger, creating a bigger problem. Meanwhile, P.T. Barnum is on the hunt to capture Nate and Ray to make his show even more exciting for the crowd.

When Sara receives a distress call from their "befriended" agent at the Time Bureau, she learns that they have been tasked with going to the future to capture a rogue time traveler. Unfortunately, the Legends make things worse by trying to protect an outlaw named Zari, to hopefully lure in the time traveling assassin. Meanwhile, Stein tries to diagnose Amaya's condition, but Nate discovers an unusual treatment that Amaya begrudgingly agrees to.

The Legends learn that Ray Palmer will die because they broke time, causing them to race back to 1988 to try and save his life. When they arrive, they are surprised to learn that young Ray Palmer has befriended a time-displaced baby Dominator putting him in harm's way with the government and the Dominator's mother. New to the ship and missions, Zari must find her place and learn to trust the team. Meanwhile, Stein begins working on a secret project on the ship which makes Rory and Jax suspicious.

When Nate thinks he has found a pattern to the anachronisms, it leads the Legends to London in 1897 to hunt down a time-traveling vampire. When they arrive in London, they run into Rip, but not everyone welcomes him back so quickly, leaving Sara to make a tough choice in the end. Amaya tries to connect with Zari, but she is still struggling with being part of the team. Meanwhile, Stein discovers what Ray and Jax are up to and is not entirely pleased.

When the Legends track down an anachronism in 1930s Hollywood, they discover it's none other than a time-displaced Helen of Troy and she's just started a war between two film studios. As the Legends try to fix history and return Helen to the Bronze Age, things get complicated when they are blindsided by the appearance of a former enemy. Sara contemplates an offer she is made, which would make the Legends leave the anachronisms be. Meanwhile, Stein and Jax find themselves in an unusual predicament.

With Sara out of commission, the team finds a new Anachronism that leads them to the jungles of Vietnam and right in the middle of the war. Ray, Amaya and Zari pose as journalists and trek through the jungle when they are lead to time-displaced Gorilla Grodd. Meanwhile, Nate and Rory run into someone Rory knows which give a glimpse into his past.

Barry and Iris's wedding brings the gang together, but things go awry when villains from Earth-X attack the ceremony. All of the superheroes band together with help from their super friends like Citizen Cold, The Ray, Felicity Smoak, Iris West and Alex Danvers to take on their most formidable villains yet. Earth's mightiest heroes - Green Arrow, Supergirl, The Flash and White Canary - lead their teams into battle to save the world.

The crossover starts on Supergirl S03E08 Crisis on Earth-X (I), Arrow S06E08 Crisis on Earth-X (II) and The Flash S04E08 Crisis on Earth-X (III).

Rattled by recent events, the Legends dive into work which finds them investigating an Anachronism in a Viking settlement in the New World. The Legends realize that the Norsemen are worshiping an artifact as their god and are surprised by the artifact's origin. For the first time, Sara is worried that they might need back up when Damien Darhk shows up. Meanwhile, Jax finds a loophole that could potentially change history, but it is a risk he is willing to take.

After Sara's encounter with Mallus, the Legends are paid a visit by John Constantine, a demonologist detective. The Legends agree to accompany him to a present-day psychiatric hospital and they are surprised to discover who Constantine is trying to help. During the exorcism, Sara, Leo and Constantine go missing, leaving Ray and Zari to try to take care of Constantine's client. Meanwhile, Amaya and Nate once again come face to face with Kuasa.

After the team returns from a mission, Zari finds herself trapped in a time loop that results in the Waverider blowing up over and over again. Zari soon begins to suspect that the answer to stop what is happening might lie hidden among her fellow shipmates' secrets. But in investigating them she starts to understand her place on the team.

When Sara decides to take some private time, the Legends pursue a lead on the whereabouts of the long-lost Earth Totem. Without Sara's knowledge, the Legends find themselves in 1717 to hunt for Blackbeard's long-lost treasure, but in true Legends fashion things go awry. Meanwhile, Ray feels guilty about something he has done and tries to make amends, which lands him in even bigger trouble.

When Damien and Nora Darhrk take Ray hostage they force him to try and fix the Fire Totem, but Ray tries to use the power struggle between them to his advantage. Ray and Nora find themselves working together in 1960s East Germany in order to fix the totem, but soon come face to face with a younger and deadlier version of Damien Dahrk. Meanwhile, Sara seems to be taking positive steps in her personal life.

When the Legends learn that a mysterious tragedy destroyed Memphis in 1954, thus eradicating the birthplace of rock and roll, they embark on their most important mission - to save music. Nate is excited to show Amaya why music is important to him and he is surprised it leads to a rock legend as well as the sixth and final totem, the Death Totem. Meanwhile, Zari helps their newest member try to adjust to the team.

When Mallus' power over Sara resurfaces, she unwittingly becomes the bearer of one of the Totems. Rory must conquer his dark side in order to wield his own Totem power to help save the crew. Meanwhile, Agent Sharpe notices that something is wrong and recruits someone unorthodox to help.

When Ava disappears, Sara and Ray set out to find her after some prodding from Time Bureau agent Gary and a disturbing truth about Ava. Amaya tasks Zari with helping train Rory in controlling his own Totem power. Meanwhile, Nate and Wally set out on a mission that goes awry when they pair with an unlikely person to try and get a Totem.

With the timeline barely stable, the Legends must tackle two anachronisms at the same time to try and keep Mallus at bay. Sara and Rip team up to stop Grodd from going after a particular target leaving Nate and Wally to stop Amaya from changing her future. Meanwhile, the Legends think they have found a way to destroy Mallus, but they will have to create an uneasy alliance with one of their enemies.

The Legends plan to vanquish Mallus by using the totems doesn't go as planned, forcing Rip to improvise. The team finds itself regrouping in the Wild West where they run into their old pal Jonah Hex. Sara leaves Ray in charge of watching Damien Darhk, while she comes up with a new plan. Meanwhile, Amaya is determined to find a way to use the totems to destroy Mallus.

After the Legends defeated Mallus and wiped the final anachronism from time, they find themselves in unfamiliar territory with the Time Bureau. All that changes when Constantine informs Sara of a new magical threat that leads the team to Woodstock. Constantine thinks he knows how to defeat the new threat, but will need the help of the team and their special klepto talents to help with his spell. Meanwhile, Nate and Rory go on an adventure leaving Nate facing someone from his past.

When the magical Time Seismograph goes off, the team finds themselves headed to the Salem witch trials. Sara notices that Zari is taking this case personally when she promises to save a mom, who is being accused of being a witch. However, the team quickly learns that there is a magical creature in the town creating problems they hadn’t been expecting. Meanwhile, Nate and Ava work together to try to keep their Time Bureau funding by proving to them that magic exists.

When the Legends discover a fugitive is hiding in 1970’s London, they realize he is part of a gang that is targeting the British Monarchy. Trying to stop the gang, they realize someone from the Legends must infiltrate them. Surprising everyone, Ray is the one to gain their trust after he is put through a series of tests with help from Sara and Rory. Meanwhile, Gary shows Nate the ropes at the Time Bureau, but it turns out to be anything other than an ordinary day at the office.

When the Legends discover that kids at a summer camp have disappeared, Sara, Ava, Ray and Constantine find themselves as the new camp counselors. At camp, Ava struggles to get along with the kids, but Constantine whips up a potion that helps Sara and Ava bond with the children. Luckily, the team finds clues to the whereabouts of the missing kids, but the battle to save them leaves one member in bad shape. Meanwhile, Rory and Zari are tasked with watching the fugitive and Rory finds a kindship with their "prisoner."

A new fugitive is on the loose in 1951 Tokyo and Sara, Zari, Rory and Charlie try to capture it. As Constantine struggles to recover, Ray knows that magic might be the only thing that can save him but must look outside the team for help. Meanwhile, Ava joins Nate and his family for an unconventional Thanksgiving dinner.

When Hank Heywood confronts Ava about the spending habits of the Legends, Nate steps in to try and smooth things over by inviting Hank on to the Waverider. The Legends then show Hank what they do by visiting 1920s Paris, trying to capture the newest Fugitive. Meanwhile, Mona is trying to make a good impression with Ava, but her over eagerness gets her and Ava stuck in a cell instead.

With Rory and Ava at odds, Sara tries to come up with a way for them to get along, but all is put on hold when a new magical creature attacks the Legends. Constantine is forced to confront his tragic past but it could have devastating consequences for the rest of the team. Meanwhile, Mona has a crush on someone she works with and gets some advice from Nate.

After Constantine breaks the cardinal Legend rule—you can’t change the past—he, along with Charlie and Zari try to deal with the ramifications without telling the rest of the Legends. Even though Zari encourages them to just fix the problem, Constantine and Charlie are determined to find another way, but only continue to make things worse.

When the Legends hear that Mona has let a fugitive go, they must head to 1961 Mexico City to clean up her mess. Mona tries to convince the Legends and the Bureau that the people responsible for releasing the fugitive were some mysterious Men in Black and not her. With no evidence to back up her theory, the Legends must decide if they should trust her and go against the Bureau. Meanwhile, Nate and Zari go on a recon mission to find out what Hank might be hiding from everyone.

When Hank commandeers the Waverider in 1973, the Legends find themselves on the run in an RV after kidnapping the President who is only able to tell the truth. With the help of Constantine, they discover the reason that none of them can lie making for an uncomfortable family road trip. Meanwhile, Nate and Zari, with the help of Nora and Gary, work together to find out what Hank is really up to.

When Mona discovers that her favorite author, Jane Austen, might be at the epicenter of a magical alert, Mona, Sara, Charlie and Zari find themselves in 1809. With Nate still dealing with family issues, Constantine and Rory perform a séance and receive a message from the other world that rocks Constantine to his core. Meanwhile, Ray and Nora are forced into close quarters.

With darkness on the rise in 2019, the team realizes that a new host of problems have risen as they have been cleaning up history. Sara tries to save Ava from a fate worse than death while battling her own demons. Nora and Constantine work together to take down a powerful demon. Meanwhile, Zari gets unsolicited advice from Mona, Charlie and even Rory.

While Ray is worried about Nora, he is suddenly faced with his own problem that forces him to do the unthinkable. Nate and Zari are stuck in an awkward limbo, so Sara devises a plan to send them on an easy mission together. Meanwhile, Charlie and Rory are approached with a lucrative offer that could upend their lives.

With Constantine missing, the Legends struggle to find a way to track him. When Sara hesitates to make a tough call, Rory steps up creating a wedge in the team. Meanwhile, Ava gives Gary the responsibility of handling the Bureau performance reviews for all the Agents.

With things getting out of control, Sara and Ava concoct a bold plan to take back the Time Bureau. But when things go awry, Zari and Charlie must work together to discover what Neron is planning. Elsewhere, Constantine is given a tough choice on who to save from Hell.

While on a mission to find Ray, Constantine and Nora discover Neron's evil plan. Nate convinces the Legends to think outside the box and suggests a dangerous plan to unite magical creatures and people to save the world.