Summer vacation begins. After graduating from high school and starting life alone in the city, you feel worn out by the noisy streets and constant social demands. One day, nostalgia strikes for the small island where you once lived freely amid nature. You contact the aunt who runs a minshuku (Japanese inn) there, and she warmly welcomes you back with a small request: to help care for her two daughters while she's away. Thus begins a 14-day summer holiday on the familiar island, sharing special days with the two girls.

**Heroine Introduction:**

- Honoka Umine (cv: Mitakarin): The older of the childhood friend sisters. Gentle and laid-back, she helps at the minshuku and is skilled at cooking. Seen as mature by others, but occasionally shows naive side. She's secretly thrilled by how manly the protagonist has become after years apart.

- Hinano Umine (cv: Raimu Fran): The younger sister. Expressionless and somewhat airheaded, but actually very handy from helping her father with boat carpentry. Has quirky tastes and brings back odd finds from ruins. Though her face doesn't show it, she's happy to reunite with the protagonist.

**Ways to Spend Time on the Island:** The sisters live freely. Explore the island with them, make naughty requests, or fulfill their wishes to grow closer. As they get comfortable, the relationship turns sweet, where they "do it" anytime.

**Fishing:** Fish at specific spots on the island. Fill the fish catalog, and the girls will come check. Collecting all fish might lead to something good.

**Erotic Scene Introduction:**

- Anywhere Erotic: Walk around with the girls and have sex anytime, anywhere. Dressing changes possible once conditions are met. Take both for 3P.

- Small Dot Erotic: Talk to girls in daily life and propose erotic acts. Enjoy special time indoors, around the island, or unexpected places.

- Large Dot Erotic: Multiple large dot H scenes included.

- Erotic CG: View HCG events in ADV parts. All erotic scenes are newly shot with full voice acting.