At the university Halloween party, Cassie Lane never meant for a costume and a mask to turn her secret crush into a forbidden mistake. Professor James Mercer has spent his career living by rules… until one masked girl tempts him past every line he swore he'd never cross. When the masks come off, neither can forget what happened. He tells himself it was one night. She knows it was something more. Now every lecture, every glance, every silence between them is charged with the memory of what they can't admit. As jealousy, guilt, and desire blur the line between duty and love, Cassie and James must choose: keep pretending…or surrender to the truth that already owns them.