'Two Can Play' and 'Check & Mate' are standalone young adult romance novels by Ali Hazelwood. 'Two Can Play' follows Savannah, a woman navigating a complicated relationship with a rival, while 'Check & Mate' centers on Mallory, a former chess prodigy who is drawn back into the competitive world and finds herself falling for the reigning world champion. Both stories explore themes of ambition, rivalry, and finding love in unexpected places.