Pranking unsuspecting strangers in Walmart is hilarious good fun.
Jack Vale's marriage is on the rocks and the trust is gone between him and his wife. It's to the point where she doesn't even believe him that he is on an innocent little trip to Walmart. Jack needs proof that he is at the store so he asks strangers to vouch for him that he is indeed at Walmart and talk to his wife over the phone. His invisible phone that is.