The invisible boy Chip intends to enter his invisible dog Max in the dog show, but when Max goes missing, Chip and his Invisible Inc. friends suspect foul play.

When the Invisible Inc. gang makes computer greeting cards to raise money to invite an author to school, they solve the mystery of the author's real name.

Gwen and Jill's discovery of some mutilated library books strangely links up with a dog show in which they have entered their dog.

When her gymnastics team's good luck charm disappears, Ti An tries to find out who took it in order to keep suspicion from tearing the team apart.

Eleven-year-old Philippa Bath, who loves mysteries, lives aboard a cruise ship where her parents are employees, and when the new captain and his son arrive, along with some royal guests, she is sure that something is wrong.

Jill makes up a fiendish plan to surprise Gwen on her birthday but is surprised herself by an unexpected turn of events.

On board a cruise ship to Parrot Island, eleven-year-old Philippa Bath suspects a new on-board entertainer of plotting to steal rare parrots.