During Fury's briefing at the Avengers Initiative, Steve finds himself staring at surveillance photos from several years ago showing a frighteningly young woman with honey gold hair and dark blue eyes. He is quietly dismayed to learn that this young submissive has worn the collar of a recently deceased mob boss for 12 years.
Steve had reservations about the deal SHIELD had made with this Bratva enforcer. While he welcomed the chance to take out a HYDRA base, he was unsure about working with this sub. As an Alpha Dom his protective instincts wholeheartedly approved of offering her a safe haven, but he was concerned that she would be a liability in the field. Subs who lose a Dominant after a long term relationship can become unstable. This sub had been collared for 12 years, she may not be able to function without a Dominant's guidance. If this mission was going to be successful, Steve would have to pay extra attention to her mental state and be prepared to step in with a firm hand if necessary.
No matter how much thought Steve put into the upcoming mission, nothing could have prepared him for his first sight of Nikita. The sub was calmly sitting in a chair, surrounded by dead bodies, using a severed head as a footrest while nonchalantly sharpening one of many knives strapped to her body. As unsettling as he found it, he couldn't deny that she was stunning. When she used her collar to light the whole building on fire, Steve was sure his concerns about her instability were well founded.
Once they are all aboard the quintet Nikita gave Clint the coordinates to the HYDRA base, then sketched out a schematic of the base and all the strategic information she remembered from her captivity and escape. Steve was pleasantly surprised by the level of detail she was able to give them and quickly put together a rough battle plan, issuing his orders to the team. He assigns Nikita to sweeping the base and setting charges with him and Bucky, so that he can keep as close an eye as possible on her.
Once the team reaches the HYDRA base, Steve was more than a little impressed with how ferociously Nikita fights. He had read the SHIELD file, but seeing her in action with her staff and blades showed him just how deadly she really is. It was eerily like watching Natasha fight. The way that she adapted to his and Bucky's fighting style allowed the three of them to efficiently sweep through the majority of the base. When they split up to cover the rest of the base, Steve felt uneasy with his inability to keep an eye on Nikita. The Dom in him felt a desperate need to be able to watch her back and protect her. In lieu of that, he listened hard through the coms for any signs of distress from the sub while trying to keep his own voice calm and steady in case she needed the reassurance.
Steve had just made his way to the catwalk around the upper area of the garage when he spotted a guard take aim at Nikita with a grenade launcher. He leaped down from the catwalk in time to catch the grenade on his shield. He was startled by her knife whistling past his face, ending in the neck of the guard. Steve watched as she pulled the knife out of the body, calmly wiping it on the guard's shirt.
Steve took point as they met up with Bucky who fell in behind Nikita as they headed out of the base. No one noticed her wounds, mostly hidden by her dark clothing, as the team reassembled on the quintet. When Steve noticed that everyone has taken a seat except Nikita, he turned to tell her to sit, noticing the blood dripping from the fingertips of her right hand as it hung loosely from her side a moment before she collapsed to the floor. Steve was the first to reach her, taking off his glove to feel for a pulse. The moment his skin touched hers, a bright light flared up between them, causing Nikita's eyes to flash open on a gasp, only to lose consciousness again as the bond settled between them.