While accompanying Pete's inventor grandfather to New York where the old man plans to sell his new invention, the Three Investigators find themselves in the middle of a dangerous spy case.
Wealthy eccentric Charles Barron is convinced that aliens are planning to fly to earth and take him away. The detective trio resolves to prove that Barron is being taken for a ride--but not by hostile aliens.
Something is fishy in Mermaid Court!First a little boy mysteriously vanishes, then a treasured statue of a mermaid disappears. An actor tells outrageous lies...a dog lover gets an unexplained bite...and lights flicker in the windows of the haunted Mermaid
