1,473 Pages


The crime-fighting dog duo of Penny and Rio are on the case again! Penny, the highly inquisitive aspiring detective is the leader of the two. While Rio is her sleepy, somewhat lazy sister dog who just wants to lie in the sun to get a tan. But when the two pair up, mysteries get solved.

Their second case, Penny and Rio: The Locked Doghouse Mystery centers around a small scared mouse named Squeaky who needs Penny's help to collect his precious belongings from a locked doghouse. The lovable and gigantic Hobbes, the Great Dane, lumbers along with Penny and Rio to solve this mystery. But can they open the doghouse in time? What exactly does Squeaky have hidden inside? Through this enchanting mystery Penny and Rio learn that they can do anything, as long as they stick together.

Reader's Reviews


"Penny and Rio find themselves paw deep in their latest mystery when Hobbes, a huge Great Dane and new next door neighbor seeks them out for their expert detective skills. Not one to be easily intimidated, Penny stands her ground and listens intently of the new case thrust upon them. The dilemma and determination of Hobbes’ friend Squeaky to get into the old locked doghouse draws in the four legged detectives immediately. And with the evasiveness of Squeaky, Penny’s curiosity is piqued further and she pleads for her sister, Rio, to quit her napping and help in finding the missing key and gaining entry. Up against an impossible deadline of less than a day, the cleverness of each is put to the test while on the case of finding the lost key. Will they make it in time?  Ms. Swanson brings to life the adventures of Penny and Rio with such humanistic characteristics the reader forgets they are on a journey with animals. Children will certainly enjoy reading about the detective skills of such ingenious dogs."-- Donna McDine, Write What Inspires You


"Penny drags Rio into solving the latest mystery and once again they steal the reader's heart with their charm and personality. Funning, endearing and engaging, I would encourage your early readers (1st and 2nd grade) to try reading this with your help. How can you not get hooked on reading with Penny & Rio? I just can't get enough of Penny & Rio!" Lisa Barker, Jelly Mom Children’s Book Review


Penny and Rio are back. The new Great Dane next door peeks his head over the fence to see if doggie detective, Penny, is around and the adventure is on. Squeaky the mouse is in a nervous panic but no one can figure out why he wants to get into an old dog house. After digging up half the yard looking for a key, Penny gets a little help from the sleepy Rio and saves the day. In a captivating story for dog loving readers of chapter books, Penny is the action dog but her sister Rio is clearly the thinker of the two. A fun read, can't wait for the next one. -- Edith Phillps, Read, Read, Read some more!


Author Jennifer Swanson does a good job of creating a clean,simple story that keeps children entertained and interested. It was charming to see how the main characters interacted with each other and I appreciated the underlying moral of how important a family can be. One of the neatest things I enjoyed about this book was that Penny and Rio are based on the authors own animals and she shares the joy and love they brought her through these stories. If you have little ones that are always on the look out for new books then I suggest you pick up any of the Penny & Rio mystery books for them to check out.   Autumn Hofeling,

Parental Guidance

  • Reading Age: 6+
  • Reading Aloud Age: 3+ years will enjoy reading aloud

This is an early reader chapter book with full-color illustrations.

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  • 2009 Mom's Choice Award
  • 2009 Royal Palm Literary Award Nominee
  • 2009 The Dove Foundation's "Family-Approved" Seal
  • 2010 Children's Book Council Bibliographies

External Links

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