Lovestruck: The Musical

Harper drinks the youth potion to get close to Mirabella in Italy and sabotage her planned wedding to Marco. As her older self, she couldn't plausibly infiltrate her daughter's social circle, so the potion transforms her into a 25-year-old woman named Debbie Hayworth, giving her the means to move freely among the wedding guests and pursue her scheme.

Earlier scenes show Harper's frustration about being excluded from Mirabella's life in Italy, establishing her desperation to find a way to intervene.

The youth potion physically transforms the drinker into their younger self, in Harper's case, turning her back to age 25. The effect allows her to adopt a completely new identity (Debbie Hayworth) and move through situations without being recognized. Harper also uses the potion on her ex-husband Ryan, extending the transformation to him.

Harper believes Marco will derail Mirabella's career and life by taking her to Italy. Convinced that marriage to Marco means giving up her daughter's dreams, Harper decides the best way to protect Mirabella is to steal Marco's affection herself, hoping Mirabella will then leave the wedding and refocus on her career.

Harper's suspicion of Marco is established early when Mirabella announces her plans to marry him.

The brown-eyed mistress Mirabella accuses Marco of having is actually Harper herself, disguised as the young Debbie Hayworth. Mirabella has heard rumors about Marco being seen with a brown-eyed woman, not realizing that woman is her own mother trying to sabotage the wedding.

Harper's scheme to seduce Marco creates the very rumor that Mirabella later confronts him about.

At the rehearsal dinner, Harper discovers a greenhouse filled with Marco's unfinished wedding vows, letters he wrote expressing his deep love and devotion to Mirabella. This finding makes her realize she misjudged Marco and that his intentions are genuine, causing her to reconsider her entire plan to destroy the relationship.

Harper's growing suspicion about Marco's character builds throughout the rehearsal dinner scenes.

Ryan recognizes Debbie Hayworth because despite Harper's transformation, something about her mannerisms or presence triggers his memory. To prevent him from exposing her identity and ruining her plan, Harper quickly gives Ryan the youth potion as well, adding him to the deception.

Ryan's recognition happens during a family gathering where he sees Harper's familiar behavior patterns.

Harper and Ryan reconcile after an emotional conversation where they finally discuss the real reasons behind Ryan's past infidelity. This honest exchange allows Harper to understand and forgive him, opening a path for them to reconnect romantically. The reconciliation is helped by the fact that both are now transformed by the youth potion, levelling the playing field between them.

Earlier tension between Harper and Ryan establishes their unresolved divorce issues.

The finale features Mirabella and Marco's wedding celebrated with a rendition of "Everlasting Love," a song that encapsulates the movie's themes of renewal, forgiveness, and enduring family bonds. Harper and Ryan also find their way back to each other during this performance, making the song a symbol of second chances for both mother and daughter.

The title "Everlasting Love" echoes the movie's romantic themes throughout, building toward this final moment.

Despite Harper's scheming and the discovery that her mother was behind the mistress rumors, Mirabella chooses to marry Marco because she loves him genuinely and recognizes that his intentions were always pure. The revelations ultimately bring clarity rather than division, and the family rallies around the wedding rather than allowing the chaos to destroy it.

Mirabella's determination to marry Marco is established from the moment she announces her plans.