The Inheritance Games Tome 2 (Relié)

OVERNIGHT, Avery Grambs went from sleeping in her car to billionaire heiress. Now ensconced in a world of opulence, riddles, danger, and family secrets, Avery is on the hunt for the one person who might hold the answers to all her questions - including why eccentric billionaire Tobias Hawthorne left his entire fortune to Avery, a virtual stranger, rather than to his own daughters and grandsons. Avery has a DNA test that proves she's not a Hawthorne by blood, but cryptic clues begin piling up, hinting at a deeper connection to the family.
Soon, Avery finds herself pulled into another game just as twisted as the first. As she works her way through puzzle after puzzle, it becomes clear that nothing is what it seems. Grayson and Jameson, two of the enigmatic and magnetic Hawthorne grandsons, continue to pull Avery in different directions, and it's getting harder to tell who her allies are and who will stop at nothing to see Avery out of the picture - by any means necessary.