When Kenichi is wrongly accused of stealing fruits, he and Hattori go out at night to solve the mystery. After a lot of struggling, the mysterious mugger is finally found. And who should be the thief but Kemumaki's cat Kagechiyo!
Kenichi is on his way home from a match when he stops to look up at a tree, admiring the fruits of it. Just then, the neighbour, a snooty man of elderly age, comes out of his house and accuses Kenichi of stealing his fruits. Kenichi gets such a shock that he runs off and leaves his baseball cap behind.
Next day, at school, Mr Koike recovers Kenichi's hat and accuses him of stealing in front of the whole class, much to Kenichi's shock and chagrin. Later on, Kemumaki is seen petting his cat and then makes fun of Kenichi, who seeks advice from Hattori upon reaching home. Hattori, being the only person so far who believes Kenichi for the fact that he didn't commit the robbery, they sneak out of the house at night to find the thief. They then discover Shinzo and Shishimaru, who were upto some naughty business, but then again, they are innocent. The then find a crow perched on the tree. Kenichi assumes he is the thief, but Hattori tells him to rack his brains harder.
The following night, Kenichi takes his camera and ninja spring shoes to the scene of the robbery. He then jumps up to find the thief but hits his head and gets knocked out.
Hattori scans the pictures, and sees Kemumaki's cat Kagechiyo and wonders if he is the thief. He and Kenichi then investigate, Kenichi jumping up and down to find out. He gets clear shots, but the neighbour comes out and starts ranting that Kenichi is stealing again, this time along with his sidekick. Hattori then takes the pictures to the studio, and then gives them to the neighbour.
The next day, Kagechiyo gets told off by Kemumaki for exposing himself, Yumeko makes up with Kenichi, and Hattori is pleased with the results.