Infinite Macabre is a toolkit book for doing Space Opera stories in the World of Darkness. The book contains a short section on the setting and brief rules on using spaceships, a long section on adapting each of the seven gamelines, and then a short section on making truly Alien races.
In the setting section, spaceships are described using the familiar five dot system, for size, weapons, armour and speed. There is also very simple rules for space combat. Apart from that, it attempts to define the setting. I say 'attempts' because the writer doesn't seem to understand basic astronomy. He refers to star systems as galaxies and writes about 'the Universe' in a way that suggests he doesn't know that stars collect in groups. Apart from that, the setting default is that faster-than-light (FTL) technology hasn't been developed yet, and instead there are these 'Stygian Gates' in every (by definition) interesting star system to allow interstellar travel. These Gates transit through the Underworld, seemingly for no other reason than to allow travel to be frightening and therefore 'interesting'.
That the writer of a Space Opera supplement starts by demonstrating his profound ignorance of space is quite disconcerting. Fortunately, it's actually irrelevant to the rest of the product. There is a lot of mention of space opera motifs such as Empires of Man and territorial control and such. I might be biased as a Trekker and Star Wars fan, but to me they made more sense if you ignore the "no FTL" default. After all, there is no point mapping territory, or even claiming it, if you can't reach it. Also, the writer inadvertantly created something cool with those Gates. In conventional sci fi, travel between galaxies is very rare. But in this setting, you can have regular if risky access to it.
The majority of the book is about the various gamelines, specifically sections on adapting them to a space setting, some story ideas, and 'new toy' rules for new abilities. Fortunately the writer knows the game rules much better than the rules of astrophysics. The adaption sections are good lists of the things you have to consider. Examples are probably best: Earth vampires are burnt by Earth's Sun, but what happens with other suns? Are they affected when not on a planet? Werewolf auspices are determined by Luna, but (again) what happens when Earth and its Moon are far away? There is also the issue of Fae Arcadia. Is it still an alternate plane, or is it now a planet in the normal Universe? You are given lots of options for dealing with these issues. The other gamelines are also dealt with, but their adaption is much easier and mostly consists of expanded possibilities. There are also guides for what the Vampire Clans, Werewolf Tribes, Mage Orders and such might be like in the expanded setting. For instance, the default setting is that the supernatural beings are not hidden, so you can have empires ruled openly by vampires or mages or others.
The final short but thorough section has the rules for creating a new character template, the outer-space Alien. The new traits allow for aliens as weird and non-humanoid as you can want. It also has brief write-ups for the standard American alien trinity, the Greys, the Nordics and the Reptoids. This section consists of 7 pages of this 30 page book, for anyone thinking of buying it to use these Aliens in an Earth-bound game.
Summary: This is a book full of useful advice for adapting the various gamelines. Werewolf struck me as the hardest to adapt and the least rewarding to do so. Working out how to adapt the Changeling Hedge is also complex, although Changeling would be a great source of weird aliens for other gamelines. The other gamelines are relatively easy.