After a brief contact with Miranda, where she expresses concern that her father is working with the Illusive Man, she asks Shepard to meet her on the Citadel, where she asks Shepard for access to Alliance resources, though she won't say why even if Shepard presses her.
She reveals that her father, after Miranda had escaped from him, created another daughter, Miranda's genetic twin sister, Oriana.
If Shepard grants her access, she then confesses that when she had headed the Lazarus Project to revive Shepard, she wanted to put a control chip in Shepard's brain, to ensure Shepard wouldn't go rogue, but the Illusive Man, not wanting to take away who Shepard was, ordered her not to.
In one of the story's loyalty mission, as well as loyalty when the Illusive Man Miranda survives and, after taking prevent Shepard from destroying the Collectors' Space Station by refusing. If Shepard is unable to negotiate, Miranda will still attack warned her of Kai Leng, and while she will kill him, he will fatally shoot her in the process.