Although at first fun and enlightening, the Journey runs into a crisis in a deep mountain gorge called Morbio Inferiore when Leo, apparently a simple servant, disappears, causing the group to plummet into anxiety and argument.

Leo is described as happy, pleasant, handsome, beloved by everyone, having a rapport with animals – to a discerning reader, he seems a great deal more than a simple servant, but nobody in the pilgrimage, including the narrator, seems to realise this.

But he is unable to put together any coherent account of it; his whole life has sunk into despair and disillusionment since the failure of the one thing which was most important to him, and he has even sold the violin with which he once offered music to the group during the Journey.

Finally, at the advice of a friend, he finds the servant Leo and, having failed in his attempt to re-establish communication with him or even be recognized by him when he meets him on a park bench, writes him a long, impassioned letter of "grievances, remorse and entreaty" and posts it to him that night.

H. H. discovers that his "aberration" and time spent adrift was part of his trial, and is allowed to return to the League if he can pass any new test of faith and obedience.