The girl they took in replaced me

The Story

Sylvie arrives on the protagonist's sweet sixteen birthday, brought home by her three brothers who demand she be treated as family. What begins as a minor disruption escalates into brutal betrayal over the following years. Jace, the youngest brother, physically shoves the protagonist down the stairs to protect Sylvie. Asher, the eldest who once vowed to shield her forever, orders her to leave the house. She departs quietly, and the brothers mistake her exit for a temporary tantrum. They subsequently relocate Sylvie to France without verifying the protagonist's safety. Unbeknownst to them, she has signed a binding contract with the family’s biggest rival, becoming their youngest chemist. This legal agreement permanently bars her from returning. When the brothers finally realize she is truly gone, they shatter.