Celi Rivera is an 11-year-old who is experiencing some new changes in her life. Her body is changing, she’s attracted to a boy for the first time, and her best friend is exploring what it means to be genderfluid. But the biggest thought swirling through her mind is about her mother’s insistence on holding a moon ceremony for Celi when her first period arrives. This is an ancestral Mexican ritual that Celi doesn’t want to have anything to do with. Can she find the strength to overpower her fear, embrace this ancestral tradition, and just be herself?