#9 The Happy Valley Mystery by Kathryn Kenny, 1962.

Trixie’s uncle, Andrew Belden, after hearing about the mysteries that the kids have solved, invites them all to spend a week on his sheep farm in Iowa. He won’t be there because he has to take a trip to Scotland, but the Gormans, who are taking care of the sheep, could use their help. Someone has been stealing sheep from the farm, and no one seems able to figure out who it is or how the sheep keep disappearing.

Although Andrew Belden mainly wants the kids to relax, have fun, and learn a little about taking care of sheep, Trixie just can’t resist the challenge to save her uncle’s sheep.  In this book, Trixie is teased a lot for her detective ambitions, and she embarrasses herself a couple of times by suspecting the wrong people. Part of the trouble comes from the fact that she doesn’t know the people in the area and who can legally be the area of her uncle’s farm.

There is a harrowing scene where Trixie and her friends are caught in a flood.  This book also develops the relationship between Jim and Trixie more.  For awhile, each of them is jealous because they think that the other likes someone else.  At the end, Jim gives Trixie a bracelet with his name on it as a sign that they are now boyfriend and girlfriend.

The book is currently available online through Internet Archive.