Masamune-kun's Revenge (2017)

S1E7 The Tsunade Island Incident

With exams behind them, summer vacation kicks off, and Masamune is eager to take his next step toward getting closer to Aki. He heads to Tsunade Island with friends to enjoy time at Aki’s summer home. Yoshino warns Masamune that if he doesn’t make any headway with Aki, she’ll spill everything to her. Upon arriving at the island, they encounter Yuigasaki, the secretary of the Adagaki family. In a moment of impulse, Masamune claims he’s in a relationship with Aki, which forces them to maintain the facade of being a couple.