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.

22-year-old Jess Valenzuela’s life is turned upside down when she meets a mysterious stranger who holds a clue to an ancient treasure linked to her long- dead father. With the help of her friend Tasha, Jess uses her knack for puzzle-solving to try and crack the clue. But they both soon realize they’re in way over their heads when Billie—a ruthless black-market antiquities dealer—joins the hunt.

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.

Trust no one on a treasure hunt. Jess begins to wonder if this is true as she suspects someone close to her might’ve leaked an important clue to Billie, but she doesn’t want to believe it. While Tasha uses her tech skills to ferret out the mole, Jess realizes the key to the next step in the treasure hunt is locked in the Rare Books Room at the Governor’s mansion, leading Jess and her friends to plot a caper during the Governor’s Ball, where Jess’s trust in her friends will be tested.

With their friend kidnapped by a rival treasure hunter, Jess and her best friend, Tasha, hatch an elaborate plan to get him back, leading to a ransom exchange on a WWII warship, where Jess realizes this treasure hunt is too dangerous to continue. But will all that change when Liam Sadusky lets her in on one of his own family secrets?

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.

With his identity finally revealed, Salazar joins Billie in the final leg of the treasure hunt, where Jess and her allies try to outwit Billie using Jess’s knowledge of puzzles and history to escape and protect the treasure.

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.

After getting captured by Billie, all hope of saving the treasure seems lost for Jess. Tasha, Oren, Ethan, and Liam try to track Jess down using Tasha's tech skills. Meanwhile, Liam finds a hidden cypher left behind by his grandpa, which holds the truth about Billie and the mysterious Salazar.

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.