Similarly sickening past (Bucky x y/n castle)

At the age of 13 y/n castle was kidnapped, and Put into a program. Though it wasn't like the usual, it was purely training for assassins.
This program was a collaboration Between the redroom and hydra, hoping to build ties called chimera. Named after a Greek mythology female, with the head of a lion and a body of a goat known as a bad omen and for its massacres.
But in the end the project between the two only builds conflict and is quickly shut down.
When y/n gets free and finds a similarly burdened man, and a new home. What could go wrong right?