Secret of the Hidden Tunnel, The

Another from the Faith Finders series from Day One, this one aimed at girls in the 10/12 age range. It's the story of Matty who is sent to boarding school when her parents go off to work in Africa (though not to be missionaries, indeed they aren't even a church going family at this point), thus it raises the issues of changing schools, leaving family, homesickness and making new friendships. However it's also a story of coming to faith through seeing others with it and slowly learning what real faith and commitment is. Mixed in with this is also a good basic grounding in what a missionary is and what they do, including the horrors that can be involved in such things as told by Miss Grace their housemistress.
It's also a story that deals with keeping faith even against the most trying situations such as bereavement, the fear of losing an ill parent and sibling and with anorexia and feeling unloved – and how faith and God can help even here.
On the whole it covers a real range of teen issues and focuses on how faith can often help and how calming and restorative prayer can be. A great book for young Christian girls who want a Christian take and a storyline with a similarity to the Chalet School books by Elinor M. Brent-Dyer