Jordan Edelman's messy dating days are over. After a few too many broken hearts, and a father who worries a bit too much, she's sworn off boys—at least for the summer. And since she'll be tagging along on her father's research trip to Nantucket, she doesn't think it'll be too hard to stick to her resolution.

But hooking up with the cute boy on the ferry doesn't count, right? At least, not until that cute boy turns out to be Ethan Barbanel. As in, her father's longtime research assistant Ethan Barbanel, the boy Jordan has hated from afar for years. And to make matters worse, Jordan might actually be falling for him.

As if that didn't complicate her life enough, Jordan's new summer job with a local astronomer turns up a centuries-old mystery surrounding Gibson's Comet—and as she dives into her research, what she learns just might put her growing relationship with Ethan in jeopardy.