Prologue

The Prologue arc is the first arc in the Oshi no Ko series. Prologue arc span the entire first volume of Oshi no Ko, and tells the story of how Gorou reincarnated into the son of his oshi, Ai Hoshino, and his childhood as Aquamarine Hoshino.

Summary
Gorou is a gynecology doctor who are a fan of the famous idol Ai Hoshino, who were taking a break because of poor health. One day, while he's working, he handled a patient who turns out to be Ai herself, accompanied by her guardian and company president Ichigo Saitou. After taking a moment to calm himself, he examined Ai and it was revealed that she's expecting twins.

Chapters

 * Chapter 1: Mother and Child
 * Chapter 2: Brother and Sister
 * Chapter 3: Babysitter
 * Chapter 4: How to Create a Smile
 * Chapter 5: Director and Actress
 * Chapter 6: Child Actors
 * Chapter 7: Failure Stems From Fear of Failure
 * Chapter 8: Hoshino Ai - Prequel
 * Chapter 9: Hoshino Ai - Fallout
 * Chapter 10: Introduction

Introduced

 * Gorou
 * Sarina
 * Ai Hoshino
 * Ichigo Saitou
 * Aquamarine Hoshino
 * Ruby Hoshino
 * Miyako Saitou
 * Taishi Gotanda
 * Kana Arima