Roger's friend Kenneth uses an unusual sea vehicle of his own design to take them to an underwater cave, where a cache of old loot gathered by the mermaids turns out to contain a lot of very valuable old baseball cards.
When the most valuable baseball card of Elizabeth's collection disappears, her mother's first new date and a suspicious baseball card dealer are likely suspects.
With his ability to travel through time by using baseball cards, Joe goes back to 1947 to meet Jackie Robinson, turning into a black boy in the process.
With his ability to travel through time by using baseball cards, Joe goes back to 1947 to meet Jackie Robinson, turning into a black boy in the process.
During a summer of baseball and baseball card trading, eleven-year-old Andy makes discoveries about his father, his grandfather, who played professional baseball, and himself.
Nine-year-old Artie Jensen gets help from his new pet Ghost Dog, an invisible pug, after someone steals the valuable baseball card his grandfather gave him.
