It's the summer holidays in the city and young Hana is trying to get her warring parents to reunite. But she's distracted from her quest one day by a couple of younger girls, nine-year-old Yoomi and seven-year-old Yoojin. As she swiftly becomes an older-sister figure to the pair, the trio's recess becomes one of imagination and adventure - from playing tricks on the landlady to going on a seaside reconnaissance - that leads to the bittersweet glimmerings of maturity.