Aquamarine Hoshino is born to a single mother, Ai, in the midst of her idol career. She is just sixteen when she has him and his twin sister Ruby. Instead, the president and his wife help her raise them. 

When they're out in public, their cover story is that they're actually the couple's children, not Ai's. Unbeknownst to all of them, though, Aquamarine is able to speak in complete sentences and walk around on his own because he's a reincarnated former fan of Ai.