Himawari-chan asks for Yūko's help to solve a series of mysterious incidents occurring at the school, involving a game called angel. Yūko meets Himawari-chan, and Watanuki is forced to work with Doumeki. Doumeki begins to learn about his true nature.

It's summer and the gang decides to spend some days in a house by the beach. For some reason Doumeki keeps asking Watanuki to call for his help, but he can't figure out why. Unbeknownst to them, there's a ghost lurking inside. When Watanuki discovers this, will he investigate alone?