Beware the bite of a king.

Khan is a king cobra shifter with a serious mistrust of anyone outside his brothers at SPSI—and he has good reason for it. As a teenager, he was subjected to the whims and experiments of a mad scientist. Since becoming part of a real family, he's thrived in his job as a close protection specialist.

One night, he meets a pretty human who interests him on a level he hasn't experienced before, but old fears and revelations force him to put distance between them. Unable to stay away, however, Khan creates the persona of a courier to deliver the venom Casey needs and find out exactly what the human will do.

Dr. Casey Jameson is working toward a deadline. He needs snake-shifter venom to continue his research and create a cure to save someone he loves. When he goes in search of a donor, he meets Khan, but he's confronted with the irresistible roughness of Khan and ends up taking the shifter home. However, when Khan finds out who and what he is, Khan leaves him high and dry.

The appearance of Roan, a courier, in his life is perfect timing, but Casey may get more than he bargains for and will soon have to think carefully about who he can trust if he wants to live long enough to complete his work.

When an old lover and boss becomes a real threat to Casey's safety, Khan must come clean and keep Casey safe before they both lose something precious.