Black Leather (слэш)

The Soldier is drawn to Tony's workshop. Later, Bucky feels guilty finding comfort there - but Tony knows more than he thinks.
Prompt: Imagine Bucky is brought back to the Tower by Steve, but he walks around like a ghost, and won't go near anyone, including Steve most days. Then he finds Tony's workshop and the bots, and spends most of his time down there, particularly once he realized Tony tends to forget he's there. This leads to Tony being the first friend he makes in the Tower, while he's even still avoiding Steve.
combined with
Prompt: When WS killed Tony's parents the mission was supposed to be kidnap Tony (so Hydra could have their own genius weapons designer) but after watching the family for weeks, Bucky couldn't let Hydra take Tony