When August Beck is out looking for his missing brother River, the last thing he expects to find is a monolith standing in the cornfield! August is certain the monolith and River's disappearance are connected and that aliens are to blame. But his best friend Tilly Wilson isn't so sure.

Tilly is an expert researcher. She has to be in order to run her own community newspaper. Tilly is always chasing down a good story, like her curious neighbor Mr. Starr, who makes art out of trash, but she isn't convinced August's theory is true. She's afraid he's a little too obsessed with aliens and avoiding the hard truth that little River might be gone forever.

Together they search for answers and they don't always like the explanations. Tilly learns sometimes it's better to let a story go, and August learns sometimes embracing the unknown yields surprising results. But between the monolith, changes within their own families, and a mysterious voice in the cornfield, both friends have an astonishing summer, one that teaches them to embrace mystery and never stop asking questions.