It's Chad Sheppard's 13th birthday, but 13 is an unlucky number and Chad's in for a big surprise! His best friend, Abner, is a big furry Sheepdog. So what can Chad do when his canine buddy vanishes into thin air? Not only is Abner invisible, but he can talk too and he's a bit of a wise guy! Science nerd Chad already has enough problems, fighting off two teenaged bullies who want to wreck his chances with Sophie, the cute girl next door. Now he has to hide an invisible, talking dog from his parents, and figure out how to get everything back to normal. That's not easy when Abner's invisibility wears off at the worst possible moments. A stolen top secret formula has accidentally fallen into Chad's hands, and it's given Abner all the powers of a super spy, including super intelligence. The government officials, (played by David Chokachi of "Baywatch" and Nancy Sullivan of Disney Channel's "Drake and Josh") wants their formula back, but so do the bad guys who stole it. Bumbling burglars Murdoch (David DeLuise of Disney Channel's "Wizards of Waverly Place") and Kane try to break into the house to kidnap Abner, and take him away from Chad forever. Nothing will stop the determined pair of clumsy crooks, not even their own stupidity. With the parents out of the house, Chad and Abner have to fight off the bad guys, get the girl for Chad, and save the day. A heck of a way for a kid to spend his birthday!