The so-called mother of all humans embarks on a millennia-spanning odyssey in Larson’s novel.

She calls herself Kikiloa, but she’s better known as Mitochondrial Eve: the woman from whom all people now living are descended. Born in “the deep night of Africa’s great rift valley” some 200,000 years ago, she was betrayed by her father, impregnated, and enslaved. In the present day, we find her living in San Francisco, taking the form of a teenage girl with green eyes and impressively curly hair, which is how she appears to her friend Hazel and her brother, Lee, who are wholly unaware of her true identity until she mysteriously vanishes. When “Kiki” then reappears, it’s immediately clear to Hazel that there’s something a bit magical about her. In fact, Kiki begins to suspect that Hazel has an extraordinary destiny to fulfill, one that isn’t shared by the countless versions of herself who have lived and died in parallel worlds. But while Lee begins to fear that Kiki is deceiving her, Paha (Kiki’s mentor) has turned trickster, bent on sabotaging Hazel through violence. Kiki must uncover his true intentions while grappling with the reality that her own life—and the lives of all living things—must eventually end.

Larson’s debut reads a bit like Sarah Hall’s Helm crossed with Doctor Who, if the latter story were told from the Doctor’s perspective. Characters grapple with the implications of their own near immortality and the unhappy reality that sometimes a person must die to prevent a timeline from breaking. Like Jasper Fforde or Douglas Adams, Larson is one of a true minority of writers who can make cerebral science fiction both lucid and entertaining. The book’s relentlessly forward-moving style never once loses momentum in the course of its 400 pages. This feat is all the more impressive given the scope of the subjects under discussion, which include prehistory, the last Ice Age, multiverse theory, synchronicity, and the end of all things. “At this moment,” Kiki informs Hazel, “I am connected to a trillion mes across a trillion branches of the multiverse”—a flash of the sublime that reads like an ancient account of a deity disclosing itself to mortals. The book’s thematic roots in the teachings of Carl Jung offer a refreshingly unconventional message: that embracing the most frightening parts of ourselves is the path to wholeness. “When we accept shame,” says a “time surfer” named Akamai, “we become ourselves. We think the unthinkable thought…We face our fears and discover beyond them bare fields enriched by fire, ready for new growth.” This idea will be familiar to fans of Jung and Alan Watts, but it’s rare to see it articulated at all—let alone with such power—in a work of popular fiction. This philosophical depth anchors the multiverse shenanigans in a tangible, and very human, reality.

An engaging time-travel romp that mashes up Jung and Doctor Who to masterful effect.