The Hip Hop Harry crew sings and dances to a song that illustrates basic geometric shapes and examples of them in everyday objects.

The Sad Man and the kids examine the properties rectangles have.

Tracy helps Calvin with his geometry homework by drawing large triangles on the side of his house. He uses basketball examples to help Calvin remember the different types of triangles.

The Earthlings consult with Chief about whether or not Sleight O' Hand stole Hacker's recharger key. Chief claims that Sleight looks like a triangle and thus committed the crime, but Inez suggests that there could be other suspects. She states that they should look at the evidence from every point of view because shapes look different at different angles. They revisit the video footage to determine if Sleight O' Hand is still a suspect.

Mr. Snatcher and his subordinates search for the boxtrolls by hitting boxes and seeing which ones respond to the impact. A couple of boxtrolls escape capture and flee to their underground civilization.