Utsunomiya Mitsuki is a world-renowned Hollywood actress constantly in the media spotlight. Her public connection to actor Kyōsuke Munakata begins with engagement rumors, unsettling Kyōsuke's son, Mira Munakata, who secretly loves his father. Mitsuki and Kyōsuke are orphaned siblings who share an enduring bond forged early in life. This bond included a sexual encounter resulting in Mitsuki's pregnancy with Mira.

Presented with a major Hollywood film role, Mitsuki chose her career over motherhood, entrusting the infant Mira to Kyōsuke. Kyōsuke raised Mira as his son, hiding the truth of Mira's parentage. Years later, widowed after her prominent film director husband's death, Mitsuki returns, her only tie to that marriage being her son, Takayuki Utsunomiya.

Mitsuki's aims extend beyond family. She actively pursues marriage to Kyōsuke to boost her fame, even leveraging Takayuki's romantic interest in Mira as part of her scheme. This manipulation worsens Mira's instability, especially after Mira finds adoption papers hinting Kyōsuke might not be his biological father. Mitsuki's Hollywood status and calculated use of relationships fuel central conflicts. Ultimately, Kyōsuke rejects her proposal, choosing his bond with Mira. Mitsuki's history as a mother who prioritized ambition over her child, and her later attempts to control family ties for professional advancement, define her role.