Duke with benefits

the long version

"Lady Daphne Forsyth is a brilliant mathematician with a burning passion for puzzles. When she learns that the library belonging to her benefactress houses the legendary Cameron Cipher--an encrypted message that, once solved, holds the key to great riches--Daphne is on the case. Unfortunately, her race to unlock the cipher's code is continually thwarted by a deliciously handsome distraction she hadn't counted on...and cannot resist. Dalton Beauchamp, the Duke of Maitland, is curious as to why Daphne is spending so much time snooping around his aunt's bookshelves. He's even more intrigued by her bold yet calculating manner: She is unapologetic about her secret quest...and the fiery attraction that develops between them both. But how can they concentrate on solving a perplexing enigma once the prospect of true love enters the equation?"--Page 4 of cover.