For the Moomins, every day is an excellent day to organize a picnic. Snorkmaiden invites Moomintroll to the beach, but when Moomintroll finds the buttons, he goes his own way. Moomintroll meets Hosul, and they immediately become friends. Hosuli decides to join the Moomins on the beach. At the same time, Moominmamma is preparing a picnic!