Accidents. (An AB/DL story.)

Waking up late for work, Jackson (17) hops on the subway train. Once he's on board, he sees the only other person on board is a girl who he later finds out is named Grace (16). The subway heads to a dark tunnel, but they never come out the other side, it just goes on forever.
But what twist will this bring? Are they just.. experiments?

ABDL Story, please be wary of the themes of this book.