The Moomins (1978)

S1E48 Cave Explorers and Pearl Divers

Sniff chases after a tiny cat and stumbles upon a vast cave. At the same time, Moomin is enjoying a game of Pearl Fisher in the ocean. Sniff convinces him to stash his newfound treasures inside the cave. Meanwhile, My, tired of the theater scene, has followed the Moomins and arrives to introduce the family to the philosopher Muskat.