It's Christmas Eve at the Monroes'. The tree is trimmed, the stockings are hung, and everyone is eagerly awaiting the arrival of Santa Claus. Except Howe. Howie the dachshund puppy is scared. Scared? On Christmas? Harold the dog and Chester the cat can't imagine why, but they intend to find out!

Despite his uncourageous name, Mewkiss proves to be a strong and brave kitten during a crisis in which his mistress's life is threatened.

A "monster" who terrorizes Bayport and a girl who runs away to join a cult are the subjects of the Hardy boys' sleuthing.

The Hardy Boys are given clues which send them in search of the treasure hidden by the Outlaw of the Pine Barrens. Unfortunately, the person who wrote the clues, like the silver he stole, has been buried for over 200 years.

The Monroes leave their cat and two dogs alone on Halloween night, unaware that their pets are about to be visited by a strange figure who might be a wicked witch.

Called in to investigate the theft of some statuettes stolen from the Eygptian Museum in New York, the Hardy brothers become involved in a deepening mystery which includes the possible overthrow of another country's government.

Their search for an Easter Island idol takes the Hardy boys to Easter Island and on to investigate the theft of government material in Antarctica.

The reader's decisions determine what happens when a boy who is spending the summer in Canada's Yukon Territory meets an alien that has come to Earth aboard a Soviet shuttle.

The Hardy boys track a criminal who plans to use an invention designed as a peaceful aid to the secret Four-Headed Dragon organization behind the Iron Curtain to harm the free world instead.

On a visit to Germany the Hardy brothers investigate the theft of plans for a newly invented submarine and the mysterious disappearance of valuable coins and paintings.