Kazuomi Ikeda

A young boy named Gusukō lives in the countryside with his parents and little sister. A string of droughts and other natural disasters tear the family apart, and Gusukō is forced to leave home and seek his fortunes on his own. Driven by a desire to improve the quality of life of his poor countrymen, he eventually joins a group of scientists called the Ihatov Volcano Department; he takes part in scientific projects to fight the natural disasters that drove him from his home.

引っ越してきたばかりのムーミン一家は、ジャコウネズミから地球に迫ってくるという彗星の話を聞く。もっと詳しいことを知るため、ムーミンはミイ、スニフと共に、おさびし山にある天文台へ向かう旅に出る。スナフキン、フローレン、スノークといったおなじみのキャラクターたちとの最初の出会いや襲いかかる怪物や彗星への恐怖と闘いながら仲間たちは旅をつづける。