Masaki feels left behind by childhood friend Shou who is now getting married to his high school sweetheart. While thinking of what wedding gift to get Shou, he gets hit by a truck! With his dominant arm out of commission, Masaki has trouble doing the house-hold chores. He decides to call Shou for help who suggests his younger sibling Ai instead. When Ai comes over to help, Masaki has the shock of his life. What will happen when they meet for the first time in twelve years?
29歳会社員独身結婚願望一切なしの真樹。
幼馴染で親友の青から結婚報告をうけた矢先、交通事故に遭い利き腕を骨折する。
家事もままならない真樹のもとに、青の妹「藍」が手伝いに来ることになった。
しかし、12年ぶりに再会する「藍」は、背が高く・イケメンの「男子高校生」になっていた！　
戸惑いを隠せない真樹を前に「まーくんのことずっと好きだったから付き合いたい」と藍は告白してきて──!?