When Baldvin and Inga's next door neighbours complain that a tree in their backyard casts a shadow over their sundeck, what starts off as a typical spat between neighbours in the suburbs unexpectedly and violently spirals out of control.

As always, Sickan has come up with a new plan. This time he wants to rob the IKEA furniture store. During their nightly break-in Sickan discovers that the store is used as a secret smuggling central for sending American computers to the Soviet Union. The computers are picked up by Soviet submarines sneaking into the Swedish archipelago. Naturally, it is their arch enemy Wall-Enberg who is behind all of this.

Kalle accompanies her parents to IKEA and they leave him in the ball pit, despite his protests. Kalle experiences some scary things but also gets to know a nice little girl.