Shota's family planned a hot spring trip for three, but his mother couldn't join due to work. Shota and his father instead invite their friend Teppei and his older sister An. An, hoping to relax and rejuvenate both mentally and physically in the fresh countryside air, finds herself unexpectedly targeted by the mischievous Shota. What follows is a mix of lighthearted bonding and unforeseen intimate encounters.