Gokuitten!

In the year 20XX, a new virus with a 90% mortality rate spread across the world. People were horrified about the chaos that could arise from it, only to discover an oddity about it - the virus can only be spread by women with large breasts. The governments of the world responded right away with the Big Breasts Isolation Law. Any women found to have D-cup breasts or larger is to be arrested and sent to the internment camp SICS - Six Chambers For The Sick.

Yuki Kishida is an ordinary, albeit androgynous high school boy who is living post-pandemic. One night, while walking home from school, a masked man knocks him unconscious. When he wakes up, he finds himself on a train to SICS, alongside other large-breasted women who have been detained. He is about to ask what is going on when he looks down at his chest.

Why was Yuki attacked and en route to SICS? And, more importantly, why does he now have massive breasts?