The Hunters discover a cryptex, but Erik secretly takes it before they can find out what's inside. Max hears from his birth parents. And the police accuse Eric of art theft.

Erik is taken to the police station, where Daniel tries to find the evidence against him. Max talks to his birth parents.The police arrive to search the house.

The kids find the stolen puzzle box and try to hide it from the police. Erik returns home but is acting suspicious. Daniel finds a clue in the museum footage. After tough goodbyes, Max leaves for Spain.

The Hunters meet a young girl named Evie – and her necklace has the same crown symbol they discovered in the cryptex! And Erik reveals that he has a special connection to Evie.

The kids find evidence that could prove Erik's innocence. But someone hacks into Sal's computer and erases the footage! And Max realizes there is something strange about how his birth parents tracked him down.

Evie's stepmom, Lucia, tries to take her back.The Hunters try to track down info on Lucia and visit Evie's old neighborhood, where they meet tech-loving, Jennie. She provides footage that gives them their next clue.

Tess finds an old Ruybosch family tree and realizes it's marked with the same crown symbol. Jenny helps Sal investigate his hacker. And a comic book publisher approaches Jake with an interesting offer.

The kids think Lucia framed Erik and decide to frame her back by planting a vase in her house. But the plan goes awry and they must work to avoid getting caught.

To save Erik from deeper trouble, the kids must get the vase out of Lucia's house before the police discover it. While Evie has her first day at school, the other kids come up with a plan to retrieve the hidden vase.

The reverse heist is on, but the plan involves many risky elements. Will the Hunter kids make it out of Lucia's house with the vase before being caught?

The Hunter kids realize one of the Relatives is a mole and devise a plan to uncover him/her. And Daniel can no longer work on the case now that they police have enough evidence to prosecute Erik.

Is Daniel working with the enemy? The Hunter kids confront him and he reveals a new piece of evidence. Each of the kids does their part to find the spy, but it is Anika who unwittingly uncovers the next piece of the puzzle.

The Hunters approach Detective Simon with their evidence, but are dismissed. Back at the house Apoll0 appears with news that he can find the hacker. A daring mission ensues and leads the kids to an abandoned railway yard.

Inside the hacker hideout they discover a map to a hidden room in the Hunter house! When the kids return home to find it, Max contacts them through the telegraph machine with one word - DANGER!

Apollo reveals the hacker's identity and plan; Anika and Jake attempt to contact Max. The Hunters confront the thief, but he escapes and locks them in the secret room.

Sal and Jennie discover the hacker's identity; Evie finds a mysterious object while searching for the crown.

Lucia makes another claim for Evie. Tess recognizes the object Evie found and thinks it will lead them to the true identity of the mole.

Tess and Sal work on discovering the mole's identity. Daniel and Anika spy on Lucia; the hacker learns he has been tricked.

Diane shows up and takes the crown when Erik is forced to go to the police station. The children finally uncover the mole's true identity.

Tess and Jake desperately try to convince relatives that the mole has framed Erik, but Sal's evidence is needed to prove Erik's innocence and stop the thieves from escaping with the crown.