You open your eyes and… find yourself on a desert island?! You and your childhood friend, Mitsuki Nanami, had not kept in contact for many years. But one day, she invited you on a trip for summer vacation. While on the trip, your ship was caught in a great storm, and the two of you ended up stranded on a desert island. Now you must explore, secure food and water, forage for supplies, and craft items in order to survive and escape the island. And through these shared hardships, your relationship with Mitsuki may begin to change.