In the village of Hinamizawa, Keiichi Maebara and his friends live their everyday lives peacefully and without incident. Having just moved to the town, Keiichi finds himself with no shortage of new friends. One of the youngest of this group, Satoko Houjou, plays many pranks on her friends and is always cheerful. But behind her smile lies a dark past, filled with personal heartache.

Despite all of the tragedy in her life, Satoko is still able to find happiness. Keiichi, who admires her resilient spirit, begins to think of himself as a brother figure and her protector. But when her uncle Teppei returns to town, Satoko begins showing signs of abuse. Keiichi longs to return his friend to her former happy self... so much so, that he starts to consider doing something drastic to keep her safe.