Each volume depicts a different heroine. Volume 1: Main character of the story is Tachibana Tsubomi (立花つぼみ), a fifth grader dealing with issues such as her mother's pregnancy, her first period, and the strange feelings she has started to get when she has been around boys. Volume 2: Main character of the story is Kusakabe Tsubomi (草壁つぼみ), a fifth grader, who encounters an alien wanting to do research of earth. It turns out he has picked Tsubomi to be his research subject. Volume 3: Shiina Tsubomi (椎名 つぼみ) Volume 4: Katanashi Tsubomi (小鳥遊 つぼみ) Volume 5: Aizaki Tsubomi (相崎 つぼみ) Volume 6: Nike Tsubomi (仁家 つぼみ) Volume 7: Yagi Tsubomi (八木 つぼみ) Volume 8: Honda Tsubomi (本田 つぼみ) Note: Won the Shogakukan Manga Award for children's manga in 2009.

Each volume depicts a different heroine. Volume 1: Main character of the story is Tachibana Tsubomi (立花つぼみ), a fifth grader dealing with issues such as her mother's pregnancy, her first period, and the strange feelings she has started to get when she has been around boys. Volume 2: Main character of the story is Kusakabe Tsubomi (草壁つぼみ), a fifth grader, who encounters an alien wanting to do research of earth. It turns out he has picked Tsubomi to be his research subject. Volume 3: Shiina Tsubomi (椎名 つぼみ) Volume 4: Katanashi Tsubomi (小鳥遊 つぼみ) Volume 5: Aizaki Tsubomi (相崎 つぼみ) Volume 6: Nike Tsubomi (仁家 つぼみ) Volume 7: Yagi Tsubomi (八木 つぼみ) Volume 8: Honda Tsubomi (本田 つぼみ) Note: Won the Shogakukan Manga Award for children's manga in 2009.