While visiting New York's Yankee Stadium with Kate's mother, cousins Mike and Kate decide to investigate the rumor that the ghost of Babe Ruth is haunting the stadium.

"Before an Astros game, Mike and Kate take a tour of the Houston Space Center and meet Commander Nicholas Rice, an astronaut. He'll be signing autographs and showing a very rare moon rock at the game later. But when it's time for Commander Rice to throw out the first pitch, he never turns up. Someone knocked him out, tied him up, and stole the moon rock! Can Mike and Kate figure out who the Astro Outlaw is?"--Page 4 of cover.

During a visit to the Chicago Cubs' Wrigley field, cousins Mike and Kate investigate why someone has been tampering with the famous ivy vines growing on the outfield walls. Includes historical note.

"Mike and Kate are visiting the Miami Marlins ballpark when some rare animals from the ballpark's fish tanks go missing"--

Through the window of their hotel room in the Toronto Blue Jays baseball stadium, cousins Mike and Kate spot strange blue lights flashing across the bullpen and decide to investigate.

Cousins Mike and Kate set out to catch the person who is selling counterfeit baseball shirts in the Texas Rangers' ballpark.

When a beloved Dalmatian goes missing while cousins Mike and Kate are in St. Louis for a Cardinals game, they rush to investigate and find a ransom note.

Cousins Mike and Kate investigate after someone threatens to tamper with the scoreboard right before the Colorado Rockies' season opener.

When cousins Mike and Kate discover that the bat and ball that Hank Aaron used to hit his 715th home run have gone missing from the Atlanta Braves ballpark, apparently by someone who wants the Braves' manager fired--Mike and Kate are determined to solve the mystery and get the stolen artifacts back.