Thin air - Kate Thompson

To outsiders, the Keane family looks content enough. They live on the beautiful west coast of Ireland where Brigid cooks lunches in a local hotel and her husband, Gerard, produces beef and sport horses on the family farm. Their children seem to be turning out all right and, if their lives are not entirely happy, they are at least uneventful.
Until one day when their eldest daughter's horse returns home without her.

Martina seems to have vanished into thin air and no one can explain why. Each member of the family, isolated in their confusion, deals with the crisis in their own separate way. Now that the fabric of normality has been breached, the family will have to come to terms with what they find beyond it.