The flock welcomes Tristan, a domestic gander who saves them from a she-wolf. Tristan looks like Martin but is much bolder and has a chivalresque side that charms Nils and the geese who decide to make him their protector. His intentions may be good but Tristan soon shows himself to be totally reckless with no idea of danger and soon unwittingly leads the flock to Smirre the fox who challenges the gander to a duel. However, there is no question of sending Tristan against the fox, they need someone experienced who knows Smirre ¿ and who better than Martin, Tristan's double?