Alex, an arsonist and lesbian, child of a heroin OD, gets adopted by Christians, and things go downhill from there. She finds herself on an inhospitable island in the care of a Christian cult (whose charismatic leader is American--thanks for that!). She meets Rebekah, a girl who age who was raised on the Kool-Aid and hadn't questioned it before Alex's arrival.
For the most part this book is more dark than light, but I was amused when Alex, Rebekah, and two others arrive on the island, and finding all the followers' usual hangouts empty the cultists come to the only plausible conclusion--that the rapture has taken their community away. Fortunately/unfortunately, they're all still alive, just in church beginning their descent to total lunacy.
The girls are immediately attracted to each other, but nothing much comes of that subplot.
I don't normally bother to finish or review books I don't like. Maybe since my track record has been so bad lately, I persevered with The Dark Light even though it didn't compel me.