After Jess discovers her late mother’s involvement in the treasure hunt, Jess becomes even more determined to unravel the secrets her mother never told her about their past. She enlists the help of her friends and Liam. This newly formed team of treasure hunters bonds as they decipher a clue handed down by the Masons and embark on a risky mission that sends them to a mansion once owned by and American icon.

For the first time ever, Jess finds herself in a puzzle-solving slump when she can’t crack the clue found in the last episode. Her personal life isn’t any less confusing as she tries to figure out if she and Liam have romantic feelings for each other. At the wake for Liam’s grandpa, Jess and her friends meet famous treasure hunter Riley Poole (from the National Treasure movies) and enlist his help. Jess’s puzzle-solving skills are put to the test when she and Riley get caught in a deadly trap.

Not knowing who’s good and who’s bad, Jess works with Billie and deciphers a hundreds-year-old clue that points to a famous 18th century landmark, and together they plan an impossible heist during an historic reenactment to retrieve the next piece of the treasure map. But things don’t go as planned, and Jess is ultimately faced with the most difficult decision of her life.

Jess sacrifices everything to confront her dad’s killer to find the last piece of the map. But that meeting rocks her world as she learns that nothing is what’s expected on a treasure hunt, propelling her to make a dangerous decision that could land her in prison for life.

It's a matter of life and death when Jess and her friends embark on their most impossible caper yet. Meanwhile, Liam teams up with his grandpa's home care nurse, Myles, in a desperate attempt to bring down Billie and her secret organization before they harm Jess.