I have never fully understood the plot of any of the books in Tamsyn Muir’s gutsy, gory, glorious Locked Tomb series. At this point, with the third volume Nona the Ninth in my hands and its predecessors Gideon the Ninth and Harrow the Ninth on my shelves, I have made up my mind not to try. Instead, I wade peacefully into every volume with the knowledge that I am going to experience some lesbian necromancers in space, and otherwise I exist in a blissful state of “head empty, just vibes.”

Notable vibes of Nona the Ninth: Dogs being good. Swordfights. A 13-year-old named Hot Sauce who’s the best cool girl gang leader you could expect to meet on any planet. Necromantic battles. A found family trying to get their sweet problem child to eat. Zombie armies. More Catholicism than you might expect! Two lesbian princes facing off. Nuclear war.

When the Locked Tomb series left off, our protagonists Gideon (sweet jock) and Harrow (goth princess) were in separate places, both in ambiguous states of aliveness. Harrow was deep in the purgatorial afterlife space known as the River. Gideon, who died at the end of Book One, was possessing Harrow’s body. As Harrow the Ninth ended, said body appeared to be in the hands of badass swordswoman and certified babe Camilla Hect, and it was unclear who was animating it.

With Nona the Ninth, we meet the entity currently inhabiting Harrow’s body. Her name is Nona, she has no memories, and it’s unclear if she might be Harrow, Gideon, some combination of both, or someone else entirely.

(Yes, this does mean Muir has written a second Locked Tomb book in a row in which the protagonist’s memories have been altered or erased in some way. Go with it!)

What we know for sure is that Nona, whose head we’re in for the bulk of this novel, is a charmer. Six months after the end of Harrow, she considers herself to be six months old. She is complacently vain, childishly impulsive, and passionately devoted to her adult guardians, her school friends, and dogs in equal measure. She loves butt jokes, finds both swords and bones dull, crushes madly on every particularly strong woman she crosses paths with, and can understand any language. Oh, and something mysterious and horrifying happens when she gets mad.

Nona is living on an unnamed planet that doesn’t appear to be a part of the necromantic Empire we’ve spent the rest of this series exploring. This planet exists in a much more straightforward universe, far closer to our contemporary world than the gothic fantasia of the Empire: a place with fast food restaurants and office buildings and absolutely no magic whatsoever. There, Nona goes about her daily life of attending school and plotting the guest list for her forthcoming one-year birthday party. (She wants to have it on the beach, and would like every dog of her acquaintance to attend, especially the one with six legs. Muir has given me her blessing to assure you that the dog lives.) In the background, dark machinations are in progress, of which Nona appears to be only half aware.

The refugees who flock to this planet consider necromancers to be zombies, and they live in fear of falling under zombie control. This political atmosphere makes matters difficult for Nona’s guardians, who include multiple familiar names and faces from the Empire — although said names and the faces don’t always combine in the ways we’re used to. The body-sharing of this universe is only getting more complicated! All of the guardians, however, are cooperating warily with The Blood of Eden, the militant anti-imperial group we learned of in the previous two volumes.

What’s going on in the Empire while Nona writes her guest list and her guardians help plot its destruction? We get a peek in that direction eventually. But before then, most of our glimpses into the Empire are looking not at its present, but at its origin. In periodic interstitials, we see John the Emperor-God in an apocalyptic dreamscape with Harrow, telling her the story of how he went from being just some guy named John to being some guy named John with godlike powers.

It’s here that we learn more about the key to Muir’s mythology, and the metaphor living at its heart. That metaphor is both more Catholic and more current than the rest of this series let on, and it comes together with such tenderness and urgency that it could, like a Lyctor on a rampage, rip the heart right out of you.

Then Nona, who urgently demands to express her love to everyone she has ever met, will bring your heart back to life again.

Nona the Ninth is a deceptive book: Its sweetness hides teeth, and then its teeth hide more sweetness. As long as you go in without expecting fancy things like being able to understand every detail of the action in a literal and straightforward way, it will treat you right.