S2 E19 Unmasked

In school, Ms. String gives a lesson on the pyramids, and Allen “corrects” the teacher (with Xelan knowledge), during which Robbie tells him to stop. They both get in trouble for talking during class. Allen thinks Miss String is an alien because of her “lies”. At the beach, Robbie is offered by Zero to take over the kiosk for the day, which she accepts.

In the attic, Allen tells Josh about the signs of a Makrob, the lying alien species.
Zero notices some of the merch is stolen, and at home, Robbie talks about it with her dad and Erika. Allen spies on Miss String and continues to think she’s an alien.
Zero talks to Robbie about the missing goods and asks her to be proactive about it.

Allen goes to school later in the day to look at Ms. String’s records and he sees it says “experiment” by his name, which angers him and he gets detention for a month. At home, Allen and Josh decide to stop Ms. String because she’s an alien and they make a containment and freezing machine.

At school, Robbie suspects Erika of being the thief and almost asks her if she’s the thief, but holds off. Later that day, Josh wheels their machine to the high school (where Allen and Robbie go to). Allen uses Xelan powers to get out of detention, and they put Ms. String into the machine.

As the boys are wheeling the machine, it falls and rolls through the street. At the beach, Robbie sees that Trycloid babies are stealing the merch and she goes after them. The machine eventually rolls onto the beach and runs over the Trycloid babies. Robbie finds all the merch in a lair. When Josh and Allen do their experiment in the attic, they realize Ms. String is a human, not a Makrob.

At the beach, Zero thanks Robbie for her help and she tells him “beach raccoons” stole the merch. Somehow, Ms. String excuses Allen’s behavior and removes him from the “experiment”, which was a seating experiment. Robbie and Erika spend time at the beach together.