Certainly not the greatest Grimmhime fic out there but fun to roll around in your head for awhile. The characters stay in character most of the time and leave you thinking "This is probably how this would happen." The notable exceptions are chapters 4, 5, 8, 9 and 13 and even it's mostly minor and done for the sake of story.
Normally I would complain when the characterization starts to go a little south but considering how this sort of pairing tends to get dark fast and stay there, a little light and sweetness is needed sometimes. Thank God we spend more time in Orihime's head than Grimmjow's. And I will cheerfully admit that, implausible or not, this fanfic should be read if only so you can get to chapter 8. All complaints I would have for it are silenced by the fact that it comes together so nicely that it just doesn't bother me. So if you have 30 minutes or so, give This Twisted Tryst