College. Yuki is 20 years old.

After graduating from high school, Yuki had decided to spend a year at community college while she figured out her major. Most of her friends went their separate ways off to colleges across the country, though Miki had opted to follow Yuki's plan as well. While they'd always been good friends, this extra year served to cement the pair as best friends, and nobody was surprised when they decided to attend the same university after their year of covering gen-eds and settling on majors. Yuki had decided to work towards a pharmacology degree, while Miki found a passion for art history.

It turned out that Yuki had one last growth spurt left in her after graduation. Her chest had gone from a strong 32C to a head-turning 36D, and Yuki's thighs and ass had gained what Miki assured her was an appealing jiggle thanks to letting her exercise habits slip in favor of focusing on her studies. Of course Yuki's older sister, Rei, made sure to remind her that she would always be the "little" sister; Rei was proud of her own DD chest that made it so easy to grab attention, and her own legs and backside were toned and firm.

None of Rei's teasing would have bothered Yuki if she'd been able to just ignore it while at college. Unfortunately for her, Rei had just so happened to pick the same university as Yuki for her grad school studies. Yuki did her best to avoid her sister's presence on campus, but it was impossible to avoid completely. The family resemblance was too strong for nobody to ask one if they knew the other at least once a semester.

College is a time for formative experiences. Yuki had no idea just how true that would be for her, as well as her sister and best friend.