Based on a game, this anime follows the "adventures" of Rachel Gardner, as she tries to escape the basement of a strange building, having woken up with no memory of how she got there. She's down on B7, a significant way below ground, and has to advance through the levels one at a time until she can escape. Unfortunately, each level has an occupant, who she must somehow get past, either by murder or trickery (each of whom in turn are trying to kill her).
These include: Danny, a doctor with an obsession with eyes; Eddie, a boy who is rather fond of the digging of graves; Catherine, a sadistic guard who wants to punish them for particular grievances, and Abraham, a priest, who just happens to be there. Luckily, on her side she has Isaac, a scythe-wielding maniac. Everyone loves a well-balanced sidekick.
The villains are all entertaining and the puzzles through which our pair are put and generally reasonably well thought out. It's a bit Saw-esque, though not quite as grim (or melodramatic). It has a decently spooky atmosphere, with some good variation in both the environments and the behaviour of the villains. Danny, as the evil doctor is particularly nasty, but Catherine's overall glee at being mean wins my "favourite character" award.
The journey of Rachel and Isaac through the floors feels like it should have some deeper meaning, and the anime tries to give it that by relating it very heavily to some unsubtle religious overtones. Abraham's input into the series is to repeatedly question Rachel about her beliefs and whether she will confess whatever sins she committed, while seeking forgiveness from god. He does this with the assistance of a lot of hallucinogenics (maybe), which turns a good half of the series into a guessing game about what is actually real, and what's just a dream.
This gets more annoying than you might think, as this cod philosophy never ends up making much sense. It attempts to be deep, but unless it is significantly more clever than it seems and is making references beyond me, it mostly fails. The biggest problem with it is that I found myself getting bored, as the plot seemed to run in very short circles, without any real advancement, even in the relationship between the main two characters.
Rachel is intended to be a death-seeking sociopath, but someone so emotionless that they don't have any drives, tends to be a terrible person to build a plot around. The fact that she is too miserable to want anything (except possibly a conversation with "god", if she can ever decide who he is), means that there's no real reason to care if she fails or succeeds. That gets even worse when, at approximately the two thirds mark, the plot suddenly seems to go backwards for some reason, undoing the slight growth that had been achieved by that point.
Very stylish, and has some nice villains, but doesn't make enough sense for me to stick with it.