My Sugar Baby Scammed Me, And I Wanted To Die.

From the back cover

Diagnosed with cancer, Lena decides to spend her remaining days indulging herself. She takes up with Julian, a poor, mute college student who is cool and distant yet wildly adventurous. To please him she pushes her body through bungee jumping, car racing, diving and skydiving, draining her savings while secretly signing organ donor forms, planning to give her heart to his ailing mother.

Then, on the Chief Doctor's desk, she sees a photo of Julian wearing a luxury watch. Dr. Evans explains that this is her son, a top student who pretends to be broke and mute for a role-playing game, and who calls the woman he has been playing with old-fashioned and boring. Lena tears up the donation forms and offers to join a painful new cancer drug trial on one condition: that the Evans family adopt her.

Julian keeps sending her cheap counterfeit gifts while buying genuine ones for Amber, and at night she finally hears his voice and follows him to an exclusive club. What began as waiting to die becomes a fight to stay alive.