Something strange has been spotted over the tree tops in the forest where Charlie Strap and Froggy Ball live, and Plåt-Niklas quickly builds a monocular to examine it. It turns out to be an emergency signal and the two friends together with Plåt-Niklas and The Parrot set out on an expedition to resque whoever is sending the signal.

When Hönan is kidnapped, the mischievous green pranksters Kalle Stropp and Grodan Boll set off on a wild chase. After many perilous adventures, they manage to rescue their friend. But they would never have succeeded without Plåt-Nicklas' help.

Kalle Stropp, Grodan Boll and all their friends chasing Sotisarna, who has stolen Plåt-Niklas propeller.