Bound to Trust. Bound Series, #1

Several Earth women have disappeared, their trail leading to Xarta, a BDSM planet. Marina, Earth intergalactic investigator, knows that solving this case means a long-awaited promotion. But in order to find the missing women, she'll have to go undercover as a bondage slave on Xarta, something the strong, capable woman wants no part of. Kaden is a Dom and a native of Xarta. He's also an Intergalactic Marshall, sworn to break up the slave trading ring.
His job is to take Marina as his submissive and train her while they're working undercover to expose the slavers and rescue the women. Reluctantly, Marina agrees to act as a submissive, vowing to both herself and to Kaden that her relationship with him is nothing but an act. Until Kaden shows her a side of life that calls to her in ways she didn't expect.