Tottoko Hamtarou OVA 3: Hamuchanzu to Niji no Kuni no Oujisama - Sekai de Ichiban no Takaramono  

Hamtaro OVA 3, Tottoko Hamutarou: Hamuchanzu to Niji no Kuni no Oujisama, ハムちゃんずと虹の国の王子さま 〜せかいでいちばんのたからもの〜

In accordance with the third installment of the Hamtaro series, which was released fourth in Japan, a character named Prince Bo descends from the heavens as soon as the rainbow vanishes. As a result, it falls to Hamtaro and his companions, the Ham-Hams, to assist him in restoring the rainbow.