The Girl Who Sails the Seven Seas was written as a continuation of the expand universe of Love Live! from previous works. It continues the story arc of the relationship between Umi Sonoda and the girl she loves, focusing on the events that solidify Umi's purpose in the relationship.

This story was written in 7 chapters by Umi alone, in chronological order except for the first chapter. The purpose of this book is to show the background and initial of the relationship, and the change Umi goes through to get to where she is in the present (in AMoF).