i loved you once: love still, perhaps

Operation Save Capsicle's BFF! is a go, but during the mission briefing Natasha sees photos of a painfully familiar face, and realizes who they're actually saving. They thought he was dead, that he died that day he fell from the train. She knows she should tell them they're wrong. Sequel to 'so i wait for you like a lonely house'. WinterWidow, time travel, backstory, HEA, AU.