The story begins immediately following the Wizards On Deck with Hannah Montana crossover, at which point in diverges into an Alternate Continuity. At the beginning of the story, Alex Russo has been confined to her hotel in Honolulu for the prank she pulled aboard the S.S. Tipton. There, she attracts the attention of Lilly Truscott, who initially mistakes her for Hannah's pop-star rival Mikayla. The two develop an instant rapport, and enjoy a fun evening in Lilly's suite (actually Hannah's, though Lilly's promise to Miley prohibits her from disclosing that fact). During the evening, they confess their feelings for their best friends (Lilly for Miley, and Alex for Harper) to one another. Feeling especially vulnerable (not to mention horny), the two girls end up in bed together.
The remaining sixteen chapters alternate POV between Lilly and Alex (with two third-person interludes) as they face the implications of their night together on their lives and relationships.
WARNING: The tropes section contains unmasked spoilers
In Lieu of the One I Love provides examples of:
- Beta Couple - Several of them:
- Coming-Out Story
- Dance of Romance - Lilly and Alex go public with their relationship during the last dance at Lilly's prom.
- Girl-on-Girl Is Hot - And how!
- I Want My Beloved to Be Happy - Lilly's a little to eager to apply this one.
- Lemon - Very much so, but hardly Porn Without Plot
- Les Yay - This story explores some of the subtext from the two series.
- Love Dodecahedron - Let's see... Lilly <=> Oliver => Miley <=> Lilly <=> Alex => Harper <=> Jackson => Alex <= Oliver. And that's just for starters.
- Pair the Spares - Used liberally.
- Running Gag - People saying Alex looks like Mikayla (both were played by Selena Gomez in canon), and Alex denying it.
- Shower of Love - Lilly and Miley's first lovemaking begins with one of these.
- Title Drop - Author trademark
- Too Much Information - Justin's reaction when Alex tells him and their parents how many sexual partners she's had (just one).
- Unusual Chapter Numbers - The story has sort of a helical chapter numbering system, in which the first chapter in the numbering scheme, and every fourth chapter after that, is a joint third-person chapter. Between those, chapters alternate between first-person chapters, one told by Lilly, and one told by Alex. For example, after the first chapter is Lilly I, followed by Alex I, followed by Lilly II, and so forth until Lilly & Alex V. It makes more sense if one ignores Fan Fiction Dot Net's automatic numbering system.
- Your Cheating Heart - Lilly and Alex were both in relationships at the time of their encounter. Oops!
- Your Universe or Mine? - Lilly and Alex's relationship starts out commuting by wand between New York and Malibu.