Trillin isn't technically a person. She's a tiny breakaway piece of consciousness from the all-devouring Endless, doomed to eventually rejoin it. But when a human witch stumbles into her world, Trillin suddenly has a new reason to figure out individuality–one shape-shifting tentacle at a time. Sian is sure important magical discoveries are just around the corner, if she can just get her portals to work reliably. Reaching the dimension of the Endless without being eaten on sight is a dream come true, and Sian is determined to explore every bit of it. For science, of course, not for the strangely adorable life-form who keeps popping up and trying to... flirt? But Trillin's world can be a dangerous place, and keeping Sian safe might risk drawing the attention of the Endless itself–which will swallow Trillin up along with all her dreams of humanity. Together, can this unlikely duo escape the Endless, figure out the optimum number of appendages, and maybe even find love?