During his trip, Timothy meets Racso, the son of Jenner (a rat of NIMH introduced in first book who is widely considered to be a traitor). Timothy and Racso arrive at Thorn Valley, but while Timothy integrates and begins receiving the same accelerated education as the rat children, Racso, coming from a colony of savage urban rats, has trouble adjusting to life in a cultured town of rodents. Racso is also burdened by his family history, as his father deserted the rats' previous colony, placing them in danger of extinction.