Halloween at Chastain proves to be just as spooky as ever when Conrad is tasked with diagnosing a young woman admitted to the hospital with extreme night terrors. Meanwhile, Devon faces his first Halloween in the ER, Nic panics over her decision to bring her newly sober sister to Mina's epic annual Halloween party and Bell finds an interesting way to make use of his new assistant.

When Conrad's attempt to surprise Nic with a lavish Valentine's Day dinner is foiled, he gives the reservation away to someone who could really use it. Mina and Devon distract themselves from all Valentine's celebrations by trying to figure out how their seemingly healthy neighbor has suddenly passed away. Meanwhile, Kit gives dating advice to a sex-injured patient, Irving hits a crossroads in his not-so-secret relationship with Nurse Jessica, and Bell decides to celebrate the day in the OR.

While looking for a distraction on Halloween, Conrad treats a group of witches who send the ER into chaos. Also, Devon treats a patient who thinks he is being haunted by ghosts. Meanwhile, on the way back from his vacation, Bell picks up a hitchhiker who is not what he seems to be.

Kit hires a surgical coach to watch over Bell and Raptor and help them brush up on their skills. Upon receiving attention from multiple women at the hospital, Conrad contemplates jumping back into the dating scene. Meanwhile, Devon works with an elderly couple.