A Summer Secret, Mysteries of Middlefield Series by Kathleen Fuller and published by Thomas Nelson.
With a twin brother and five younger brothers, Mary Beth Mullet’s house is in constant chaos. Her parents don’t seem to mind the noise, but she needs a break from all the pestering and babysitting. It’s the summer before eighth grade, and Mary Beth plans to escape to her secret place as much as possible. The old barn in the neighboring field is dangerous, and her parents have forbidden her to go there, but she escapes to it as often as she can.
Mary Beth soon discovers she is not alone in the barn. Someone is living there; someone who needs help. Can Mary Beth help the stranger without losing her secret place? And what if the barn is as dangerous as her parents say it is? Readers will identify with Mary Beth’s struggles for peace and independence and be engrossed in the excitement and danger of A Summer Secret.