Rising Flame — Elaina John

Lily Malloy's life changes irrevocably the night a dark stranger shows up at her door. She soon finds herself growing increasingly attracted to this mysterious man. When Lily is forced to rely on him to find her sister after she goes missing, Lily discovers a secret that could mean life or death. When Dex's planet, Jheta, is destroyed, he and his people travel to Earth for a new home. By chance, he stumbles upon fascinating, beautiful Lily. Haunted by the truth of his identity, Dex knows he can never have her. Yet that doesn't stop his attraction to her. When a threat jeopardizes the lives of Lily and the Jhetans, Dex must fight to protect them, even if it means his own life.