Taking place in the past it offers a view at the Saiyuuki quartet before their formation and their journey to the west. First OVA starts with Sanzo and his master, also with Ukoku (known as a later Ni Jianyi). Second OVA shows first meeting of Goku and Sanzo. Third OVA considers the events after Hakkai's sins and his trial (that we know from first season of "Saiyuuki") and his decision to live in Gojyo's house.

On the final day of summer vacation, Kokona Aoba is ready to spend some long-awaited time with her mother, but these plans are unfortunately canceled due to work. Opting to go outside instead, she takes a stroll down a familiar path—one where fond memories appear at every corner. Later, in the middle of autumn, Hinata Kuraue and Aoi Yukimura are looking through a scrapbook of their childhood. Snooping around in Aoi's room, Hinata finds that she has kept a strange acorn as a keepsake, but doesn't remember the reason why. As its discovery dwells on her, a wave of old memories comes forth, causing her to reminisce about a forgotten event from her childhood. From time spent with loved ones to promises from the past, Yama no Susume: Omoide Present follows the three girls as they cherish old memories while crafting entirely new ones to remember. [Written by MAL Rewrite]

The science lessons are short "omake" bonus features originally present on the first two volumes. Each short lasts around two minutes, and stars super deformed versions of Noriko, Kazumi and the Coach explaining the various scientific aspects of the series. (Source: Wikipedia)

Katari, a young girl who dreams of becoming a novelist, writes a love letter to a boy at her school. Unwittingly, she is creating a "short story" that will move a little girl's heart.