When Natalie McCullough-Schwartz finds out that her crush, Sebastian Delacroix -- a smoking-hot musician who went to her high school -- is back in Philly to play a show with his band, the Young Lungs, she takes it as a sign to make contact. Again. “Again” because they shared that moment at the pool party in June. It was fleeting, but now that he’s back, Nattie wants to see if there was ever anything more. Then she hears the song. The Young Lungs’ new single is “Natalie” -- an ode to a girl Nattie can’t believe could be her but secretly wishes is. Then there are her confusing feelings for her good friend Zach, which could just be a side effect of being the only two straight kids in the school’s gay-straight alliance. As the song becomes a major hit and her once-normal life is upended, Nattie questions whether her encounter with Sebastian was the stuff love songs are made of -- or just a one-hit wonder.