Let's☆Lagoon

A man named Yamada wakes up stranded on an isolated island with no memory of how he arrived. He discovers his sports bag, leading him to believe he was on a school trip. With limited supplies and no sign of passing ships, he resolves to build a boat to escape. His solitude is broken when he encounters a girl named Imaise Chika, who is eating his food. The story includes a chapter labeled 30.5 in Volume 3 and an epilogue in Volume 6.