It had been a long day. The Avengers had been on a mission, they all knew it would be dangerous... but they certainly didn't expect this. Everything was going as the plan, but then something happened. They heard a gunshot and a few seconds later they saw Natasha falling unconscious from a building. A moment later all the Avengers were in the hospital waiting room, until a doctor arrived with the news

Doctor: "Ms. Romanoff is in a coma, it is not certain whether she will ever wake up"