MacTaggert's memory was wiped by Charles Xavier in 'X-Men: First Class', reported Entertainment Weekly.
"She's a significant character in the movie. We ended 'First Class' with Charles having wiped portions of her memory of her experience with the X-Men. They are, essentially, strangers to her when she meets them," screenwriter Simon Kinberg shared.
He teased fans might expect more storyline between Xavier and MacTaggert.
"It's certainly a rich relationship that we started to dig into in 'First Class', and would like to mine more in this one," he said.
Directed by Bryan Singer, the movie is set for release on May 27, 2016.