ONCE UNMASKED, THIS IS ONE KILLER WHO WILL NEVER BE FORGOTTEN! Cassandra Cain has solved the murder, uncovering the killer's identity in the process. The only problem is that she is now trapped within a prison in her own mind! To stop the next murder, Batgirl must escape the labyrinth of her memories and survive one final confrontation with the past that made her. And when the true meaning of forget-me-not is finally revealed, it may be the one thing Cassandra was never meant to remember. The shocking end of this arc will leave Batgirl questioning everything!