Quick Synopsis – Myung and her sister Laleh are the sole inhabitants of the whale of babel. They roam within its cosmic chambers, speak folktales of themselves, and pray to their creator, the Great Wisa. For Laleh, this is everything. For Myung, it is not enough.

When Myung flees the whale, she stumbles into a new universe full of people, shapeshifting islands, and argumentative ghosts. In her search for Great Wisa and her longing for her sister Laleh, Myung sets off on an adventure that will unravel the mystery that has confounded everyone for centuries: the truth about the mad sisters of Esi.

Song This Reminds Me Of – I’ll Follow You Into the Dark – Death Cab for Cutie

Publication Date – Aug. 5, 2025

Bookshop Link – Mad Sisters of Esi by Tashan Mehta (I receive a small commission if you use my link)

Content Notes – There is a brief depiction of self-harm in the later chapters of the book. There is some general violence and a little bit of body horror.

Rating – ⭐⭐⭐⭐⭐out of 5

Review – I tend to be stingy with my 5-star reviews and this book earned it. It almost made me cry. The love the two pairs of sisters (Myung and Laleh) and (Magali and Wisa) have is so vast. At times the story was so heartbreaking, I felt like I wasn’t just a reader, but a listener leaning my ear against the door as these stories are told. I felt drawn in and I had genuine compassion for the loneliness and empathy for the otherness. Also, the way Tashan describes space as a black sea and planets are just islands, brava! I loved this analogy, and it honestly made the book easier to understand.

We start the book in the belly of a whale, a cosmic whale that contains it’s own world. There are two sisters, Laleh and Myung. Laleh is practical and Myung yearns for something more. They don’t truly know anything of life outside the whale, other than they were created by the Great Wisa. When Myung leaves to explore the Black Sea and find the Great Wisa, the story really takes off. The narrative is told spread out amongst different POVs, journal articles, and journal entries. We mostly follow Myung as she searches for a way back to the whale and her sister. But what Myung finds is a story spanning centuries and how the love of two sisters created a universe.

I feel like I could rave about this book, but I really don’t want to give away spoilers. Magali and Wisa are sisters by desire, not by blood. The found family aspect is done so well in this book. Wisa is presumably an orphan on Esi when Magali’s grandfather takes her in. From there we learn about the madness of Esi and the festival of madness. Magali’s community is what the book calls luddites, they don’t condone the madness of Esi and cast out or even kill people who succumb to the madness. But is the madness truly bad or is it simply people who don’t conform to the societal ideal of normal? I felt like Tashan really does a good job of wrapping complex topics into the narrative of the story.

If you like heartfelt science fiction and an interesting take on worldbuilding, I think you’ll love this book.

Thanks to NetGalley and DAW publishing for the advanced copy, all opinions are my own.