Luckenbooth, the third novel from the bracingly good Scottish writer Jenni Fagan, defies any sort of neat description. Let’s just say that it was, for this reader, no less powerful in its effect than the 1994 film Shallow Grave — Danny Boyle’s debut, and a defining movie for Generation X. In that now-vintage piece, Boyle showed us that Edinburgh’s imposing tenement buildings were perfect settings for tales about mayhem and murder.

Busy though the novel is, it can be repetitive, with frequent scrawls against existing power structures. (“We are all at the mercy of and malleable to the programmes that raised us – whether they be religious, or class-based, or gender-biased” is not a fun sentence to read in a novel.) But Fagan gives us more than enough Nazi spies, cloven-hoofed phantoms, orgies, witches, murders and fake ectoplasm to make up for it. After all, the most unforgivable oppression of all is boredom: “Making things normal seems the goal of modern society and it is so tedious.”

On underlying misogyny Fagan is especially perceptive, although there is a slight problem here. The work is clear about the reality of evil (and it not really having much to do with horns or cloven hooves), but less certain about the theodicy; the why of evil. Udnam is monstrous, but he remains a work of motiveless malignity, a black king on a chess-board with no white. Luckenbooth is a daring book, and beautifully written, but understanding the problem and suggesting an answer are different things. “Ideology” may be the enemy, but how does one understand other ideologies or change one’s own? It brings me back to MacDiarmid, as the first word of the line of the poem that stands as epigraph is omitted. The complete line reads: “But Edinburgh is a mad god’s dream.” More space for the but.

The problem here is one of unevenness. There are memorable creations, such as Ivy Proudfoot, recruited into the war as a secret operative. But others are ciphers for Fagan’s (impassioned) thoughts on inequality, homophobia and racism. The worst offender is the beat poet William Burroughs, who treats us to several draining pages on his theory of language Fagan’s prose is poetic, high-octane, built on punchy sentences. Arresting descriptions of the city and its weather abound. This is not a novel that lacks energy — but it can be hard work to keep up.

So Luckenbooth isn’t a historical novel, and it might not be a novel at all. Although the characters cameo in each other’s chapters, each story is essentially individual, making Luckenbooth more an anthology than a single narrative. Some parts succeed better than others. A Tarantino-esque hot lady gangster is exhausting; a middle-aged female medium has appealing shades of Victoria Wood.

But — like the mermaid Levi builds from bones and falls in love with, like the cut-up writing we see Burroughs composing — there’s a force in Luckenbooth’s bizarre assemblage that could come only from an author ambitious enough to risk making a mess.