Kill Box Checkmate. The World of Lizzy Ballard, #3.5

Louise Mortensen has spent her life moving other people around the board. Now she's the one with her back to the edge, with only one move left. With her empire in ashes and her freedom gone, Louise Mortensen-Lizzy Ballard's most dangerous enemy-has become an unwilling guest of reclusive billionaire Theo Viklund, forced to lend her genius to his nefarious pursuits. When a desperate opportunity presents itself, Louise eliminates her captor and assumes his identity to buy herself a path to freedom-if she can crack the biometric locks guarding his fortune.
The key stays maddeningly out of reach, until Viklund's brother arrives, hunting for the truth behind his sibling's silence. He may hold the clue Louise needs to seize Theo's riches-or he may be the one player she can't outmaneuver. And the nearer Louise gets to her goal, the harder it becomes to tell whether she's the one closing the trap, or the one being maneuvered into a corner with nowhere left to run.
KILL BOX CHECKMATE is a chilling novella set between THE IRON RING and SCARE CARD in Matty Dalrymple's Lizzy Ballard thriller series-a study of cold-blooded ambition, deception, and the lengths one ruthless woman will go to reclaim her freedom. Told from the perspective of the series' most fascinating villain, it's a story for anyone who has ever found themselves rooting for the wrong side. In a game where every piece is expendable and the board has no safe square, will Louise checkmate her enemies-or be left with no move to make?