This novel, by Trevor Baxendale, was published by BBC Books in 2007. It features the Tenth Doctor, as played by David Tennant, and his companion Martha Jones.
The Doctor and Martha arrive in an English village that is right out of Marple or Midsomer Murders. The Doctor is immediately drawn to the well on the village green.
Elsewhere, three young men are tunnelling towards the well in an attempt to find the treasure rumoured to be buried it.
What they find is an alien being of enormous power that is rising from a centuries long slumber. Should it fully awaken then all life on earth will be threatened.
The is a well written and hugely entertaining story. The characters are nicely drawn and Baxendale captures the personalities of the Doctor and Martha perfectly.
The mystery of what lurks beneath the well is maintained for just about the right amount of time before the Doctor realises what is going on.
The conclusion, relying on (literally) brain power is as satisfying as it is interesting.
One of the better novels in the New Series Adventures.