Tsukasa Tenma is a bright and noisy child. Due to the fact that his younger sister Saki is often ill, he often stays at home alone and his parents hired a nanny Rui for a couple of days. Tsukasa, of course, understands that his sister is sick and needs more attention, but still he sometimes becomes very sad to be alone. A theater show he saw as a kid impressed him so much that he made it his ultimate goal to become the greatest star in the world. He's a supportive brother to his frail sister.