El refugio secreto (El Sendero del Guardabosques, 5)

Lasgol and his companions have finally become forest rangers. The four long years at camp and the grueling tests they faced are now behind them. Now they must decide whether to take the elite specialty tests. If they do and pass, they will gain access to Specialist Ranger training. To do so, they must travel to a remote location no one has ever heard of: the refuge.