Dog and Hat are practically inseparable, and when the dots on Dog's favorite shirt disappear down a storm drain, the two friends descend into the sewers where they encounter many obstacles and unforseen dangers--and come face-to-face with an alligator.

"When Reddie comes over to Archies house excited to go to the big Hat Day party, she is surprised to learn that he cant make it. He has lost his favorite hat! Luckily, when it comes to finding things (and hats), two heads are always better than one! So Archie and Reddie set about trying to locate it. The only problem is Archies home is a little messy. And Reddie has no idea what this hat looks like. And, oh, Archie also has dozens and dozens of them...