Frank and Joe end up in a haunted house and a cemetery when they follow two men trailing their father, Fenton.

An unseen intruder breaks into the Drew home, stealing documents that will allow Nancy's aunts, Ruby and Lela, to sell their farm. While Nancy's father goes to the State Capitol to replace the papers, Nancy heads to the Farmhouse where she is plunged into a series of strange events that lead her deeper and deeper into danger.

The stage is set for mystery when Nancy and her friends decide to produce a 20 year old play in order to raise money for a youth center. The play is to be presented at the allegedly haunted Palace Theatre. When members of the original cast arrive in town, strange events begin to occur both onstage and off. Nancy must figure out why the actors have come together to appear in her modest production, or the drama might just end in real life tragedy.

Nancy and the brothers team up to find Fenton Hardy, who disappeared while investigating a series of European art thefts.

Allison Troy's Transylvanian rock concert has locals fearing a reawakening of their most notorious denizen.

After Joe Hardy's fiancée is killed by a hit-and-run driver, the FBI won't let the police arrest the man until their own case against him is finished. Joe takes the law into his own hands and goes undercover as a rich gambler with underworld connections.

Joe Hardy is still haunted by memories of his dead fiancee, but has to focus his mind on the case when Jocco's girlfriend overhears him talking to the police on the phone. Meanwhile, Frank Hardy tries to help Joe by going undercover too, but Jocco finds out and traps Frank in a shark-infested area.

Frank and Joe Hardy are assigned to go to Puerto Rico to protect a senator's daughter from an international blackmailer known as the Scorpion.