Mystery in the Mansion (Case Closed, Bk. 1)

Carlos Serrano has never solved a mystery in his life. But when Carlos's mom gets sick with a nasty flu on the morning of an investigation that could save her failing detective agency, Carlos takes on the case.

Now, with the help of his best friend, Eliza, and her wild little brother, Frank, Carlos must uncover a mystery involving an eccentric local millionaire, anonymous death threats, and a buried treasure. But with tricky riddles, cagey suspects, hidden secrets, and dozens of impossible choices, they need your help!

Can you help Carlos and his friends find the culprit and save Las Pistas Detective Agency? Or will it be case closed?