Laura and her class are going hiking on a field trip to the mountains! The Ham-Hams would like to tag along too, but having missed the bus, they figure it would take them about 3 days of ticky-tickying to get up the mountain. However, Panda introduces his brand new hand-made solution: a Ham-Ham locomotive! All board the new train excitedly. The journey however, is full of difficulties.

At Laura’s school, something strange is happening. Everyone’s shoes are disappearing! So Hamtaro becomes a private investiham, and with his magnifying glass, goes on a hunt for the culprit.

Kana is very, very mad at Laura! She thinks that Laura leaked a secret that she promised to keep! It’s all a big misunderstanding, but now the two best friends aren’t even speaking to each other. Hamtaro and Oxnard are so worried that Laura and Kana’s friendship is over forever. So worried, in fact, that Hamtaro forgets to fulfill an important promise he made to Boss to help Bijou clip the leaves outside her window.

Mimi’s father’s birthday is coming up very soon, but Mimi has no idea what to give him as a present. She really wants to do something special for him, so when she sees one day how emotional he gets when he hears Maria playing the piano, Mimi decides that she is going to learn to play something for him.