Unable to conceive children and desperate to be a mother, a gifted young teacher comes to work for a family that has been beset by tragedy and serendipitously changes all their lives for the better

I think you have to work with the word “comes to”… this has to be a something she has to do … or else…

So maybe something like..

Unable to conceive children and desperate to be a mother, a young teacher loses her job and therefor comes to work for a man and his disciplined children while he looks for a suitable wife.