Dylan Mayfair, originally thought to have died in an accident as a child, was actually alive. Her mother, Katherine, had replaced her with another girl after the real Dylan died, to protect herself from her abusive ex-husband.
In the series, Dylan Mayfair is introduced in the fourth season as the daughter of Katherine Mayfair, who moves back onto Wisteria Lane. It is later revealed that the original Dylan died from a tragic accident involving a wardrobe falling on her when she was a child. Katherine, in a panic and fearing that her abusive ex-husband would use the accident to take her other daughter away from her, buried her daughter in the woods and adopted a girl from an orphanage who resembled her deceased daughter.
The new Dylan grew up without any memory of her early childhood or the accident. Throughout the season, she begins to uncover the truth about her past, including the fact that her mother has been lying to her. The mystery unravels as she discovers a note she wrote as a child, which leads to her learning about the real Dylan’s death. Katherine had kept the truth hidden to protect Dylan from her ex-husband, Wayne Davis, who was abusive and had been searching for Katherine and Dylan to harm them.
The storyline reaches its climax when Wayne takes Katherine hostage, and the truth about Dylan’s past is fully revealed. In the end, Wayne is killed, and the Mayfairs are able to move on from the dark secret that had haunted their family for years. Dylan eventually leaves Wisteria Lane to attend college and start a new chapter in her life.
