Hamtaro: Rainbow Rescue is a Game Boy Advance game developed by AlphaDream and published by Nintendo. The game is the fourth Hamtaro title for Japanese audiences while it's the third for western audiences. It was released in Japan and PAL regions only, however there were plans for a North American release. This game was poorly distributed in many countries which makes copies of the game rare. The game was preceded by Hamtaro: Ham-Ham Heartbreak and succeeded by the non-adventure game, Hamtaro: Ham-Ham Games.
The game involves an extensive plot. One day while playing outside, Bijou witnesses a great rainbow. The rainbow disappears and Prince Bo falls to the ground. The Prince states that he can make rainbows by using his umbrella. He tries to prove it to disbelieving Stan and the rest of the Ham-Hams, but realizes too late that the colors on his umbrella are gone! And thus, Hamtaro and his Ham-Ham friends must set off on a journey in order to collect things that are the proper color for Prince Bo to use for his umbrella so he can create a rainbow to return home.
Certain minigames are needed to reach the colors, and the player must have certain Ham-Hams in their party in order to play them. For example, Sandy is needed to ride pigeons, Bijou is needed to collect falling petals, and Penelope is needed for rolling on top of cans to get across small streams.
In addition to the original Ham-Hams, the game contains some additional characters, most of which were never seen in the English anime. These include Prince Bo, who is the prince of Rainbowland (a castle that is made of clouds); Flora, or Nurse-Ham; Tux; and other various characters.