Sankarea (OVA)

Episode 0 - "Fate is... Really..."
Seven months before Chihiro first met Rea, he, his father, Mero and Ranko travel to Tohoku to help sort and move large book collection of father's brother. Along the way, they pass a bridge that seems familiar to Chihiro somehow, which leads him to question why he remembers so little about his mother, Yuzuna. Meanwhile, Rea, who had just finished middle school, faces abuse from Aria as she vents her drunken frustrations on her.

Episode 14 - "Body of a Zombie... Heart of a..."
As Aria feels lonely without Danichirou, she falls asleep in the bath. Meanwhile, Chihiro and his family discover a strange girl lying under their temple, who doesn't appear to want to say a word to anyone. When Rea searches for her when it is time for dinner, she is pushed down the stairs. The next day, they discover all the nearby hydrangea leaves have been torn apart, and later that night Rea spots the girl making a move on Chihiro.

(Source: Wikipedia)

Note: Bundled with the sixth and seventh limited-edition volumes of the manga.