The Only One To Thaw The Ice
Captain Cold x Diamond a.k.a Gaige
Diamond hates being called by her real name unless it's Leonard Snart which she soon realizes and goes by Gaige. She got that name because she's an engineer, a brilliant one at that. She's part of the Flash's team and works part time at Jitters for money. Her life totally screws up when she meets Leonard Snart, as does his.
Turns out she's another diamond he would steal, except this one he would keep forever.
A hopelessly romantic story...