Grampa becomes involved with a couple of con men over a dog. He realizes they are trying to cheat him, and with the help of George MacMichael, they turn the tables on the crooks. Meanwhile, the entire McCoy family has become so attached to the dog, Mac, he becomes a member of the family.
| Name | Type | Role | |
|---|---|---|---|
| Herb Vigran | Guest Star | ||
| Don Beddoe | Guest Star | ||
| Barbara Wilson | Guest Star | ||
| Dick Ryan | Guest Star |