The Catch by Yrsa Daley-Ward

Twin sisters Clara and Dempsey have always struggled to relate, their familial bond severed after their mother vanished into the Thames. In adulthood, they are content to be all but estranged, until Clara sees a woman who looks exactly like their mother on the streets of London. The catch: this version of Serene, aged not a day, has enjoyed a childless life. Clara, a celebrity author in desperate need of validation, believes Serene is their mother, while Dempsey, isolated and content to remain so, believes she is a con woman. As they clash over this stranger, the sisters hurtle toward an altercation that threatens their very existence, forcing them to finally confront their pasts - together.