Black Widow, Vol. 2 #1 (2000)

Breakdown, Part 1
Nick Fury has an operation in mind that requires both Widows. Yelena Belova is captured, tranquilized, and subjected to reconstructive surgery that gives her the appearance of Natalia Romanova. Meanwhile, Natalia takes on Yelena's appearance. When Yelena wakes up in Natalia's apartment and finds Daredevil treating her like Natalia, she assumes she's forgotten a mission and starts acting as such.
Release Date: 2000