At Seventeen S1E1

After parting with her six childhood friends for several years, Takumi decides to return back to her hometown to reunite with them. However, her six friends worry about her comeback as she's a real trouble-maker and has made their lives very miserable in the past. Slowly, they come to realise that they are wrong about Takumi, and just then she disappears before them once again, leaving behind the sweet memories they have together at the age of seventeen.