普通攻击是全体攻击而且能二次攻击的妈妈你喜欢吗？ OVA

As a reward for their previous quests, Masato and his party are invited by Shirase to a resort beach. The group immediately starts having fun in their swimsuits. However, Masato alone cannot honestly enjoy "going to the beach with his mother." Amidst this, by a strange twist of fate, Masato hits his head and loses his memory! Recognizing Mamako, who calls herself his "important person," as a "beautiful older sister," Masato becomes drawn to her and tries to fulfill her wishes one after another. Wise and Medhi watch over them for a while, but the situation turns dire as Masato begins to lose interest in adventuring in this game. Will his memories ever return?