A marine biologist, Leah, is employed by a creepy research centre and her job involves going on mysterious missions on submarines. Whilst on one of these missions, the vessel is pulled to the bottom of the ocean, in an read unnaturally devoid of life. On land, her wife Miri mourns her, as the initially anticipated three weeks turns into six long months. When Leah finally resurfaces, she fails to really come back, permanently changed in her body and her mind. The book alternates between the perspectives of the two women: Leah aboard the submarine, trapped under the sea, and Miri, missing Leah, at first literally, and then emotionally.

I most enjoyed Miri's side of the story, especially in the first half of the book. Her remarks about their straight friends were funny, the account of the relationship sweet, and the sense of longing for someone who is absent or sick was touching, making parts of the book a convincing analogy for loving someone who is unable to love you back, be it because of depression, because they fell out of love, or because they're turning into a fish. The horror-fantasy scenario was set up well, especially at the beginning, when the mysterious undersea world merges into hyper-realistic experience of waiting on the line and speaking to inhumane phone operators. In the end, though, it never comes together: too vague to be interesting as a fantasy, too tacky to really work as an analogy (especially the 'climaxes', i.e. the part where Leah meets the monster under the sea, and the ending. Listened to the audiobook, which was very well done.