In the summer before eighth grade, Marco Suarez kissed his best friend Sally Blake. This was his first spark.

And since then, whenever he's thought about that moment, he's traveled through a wormhole--of sorts--to relive those brief seconds when time sped up (or, rather, his view of time distorted) and he kissed her.

And then, at the end of that year, she disappeared, leaving in that way that people sometimes leave--alive and well and somewhere out there but gone, nonetheless. She never even said why.

And now in their senior year, Sally unexpectedly returns and Marco is shaken. Still, he holds tightly to his carefully choreographed life. A life that is full of reasons why first sparks don't matter:

Reason 1: He has a girlfriend. Her name is Erika Richards.
Reason 2: He's leaving on a full scholarship to college.
Reason 3: He's busy with his friends and making money to help support his family.

But as Marco navigates the final days of high school, he learns that leaving home is never easy and a first spark is hard to ignore.