What's the Name of That Book??? discussion

I'm looking for a strange outer-space romance I read a while back. All I remember is the heroine was locked away in a spaceship (under the flooring perhaps) by the captain. Then this alien guy appears to exchange cargo with the captain and the woman sneaks off and hides onto the alien's ship where she spends a week in the walls (without food or anything) and is caught because she begins to smell pretty bad...
I think her and the alien are 'soul mates' too.

I have read this, give me a minute to find out the name.

Demon Possession (Shadow Quest, #1) by Kiersten Fay!

Demon Possession for the click for Desiree's suggestion.

Thanks, I'm on my phone. I'm glad I could help!!

That's it! Thanks so much Desiree (& Ann)!!