Sputnik Sweetheart is a novel that delves into the complexities of love and human longing. The story revolves around Sumire, an aspiring writer with a unique fashion sense reminiscent of a Kerouac character, who finds herself in love with a woman seventeen years her senior, named Miu. Sumire's best friend, K, a primary school teacher, grapples with his own feelings for Sumire, which remain unspoken.

As Sumire confides in K about her life's big questions, such as the nature of sexual desire and whether to confess her feelings to Miu, K contemplates revealing his unrequited love. The narrative takes an unexpected turn when Miu, in a state of desperation, calls from a Greek island to report that Sumire has mysteriously disappeared. This event thrusts K back into Sumire's enigmatic world, leading to a search that is fraught with ominous visions and a haunting sense of absence.

Sputnik Sweetheart is a subtle and evocative exploration of the yearning that drives us to seek connection and the profound impact of love and loss on the human psyche.