It’s a case of hidden identities for brother detectives Frank and Joe in the in the eighteenth book in the thrilling Hardy Boys Adventures series.

Ever since the Bayport Times article about their past cases came out, Frank and Joe have been getting calls for help in solving everything from lost keys to lost treasure. The boys can barely stand to answer their phones anymore. But when Principal Gerther calls, they pick up.

Turns out, Principal Gerther’s cousin, Agatha, has noticed a string of strange disappearances in her apartment building. One person after another is entering the apartment next door…and they never come back out. Agatha would know, she never leaves her apartment!

Frank and Joe make some inquiries and realize each and every person that has stayed in apartment B3 has never returned home. What’s worse—most of them have left a trail of debt or angry partners behind them. There are almost too many suspects to count!

Are these two teenage detectives up for the job? Or is The Hardy Boys reputation about to be tarnished?