Athena convinces Zeus to make Calypso lets go of Odesseus. He eventually gets home and finds suitors trying to take hs wife and kingdom. He finds his allies and kills all of the suitors. This is the lowest time because he sees his familly and kingdom struggling without him and he has the challenge of killling 100 men with some help but not much.
He then finally talks to his wife and after they have a conversation reunites and are happy. But the people are mad that 100 people are now dead so Athena the mentor who helps Odesseus many times fixes the problem and returns the kingdom to peace and Odesseus is happy with his life and kingdom. This is the mentor, reward and crossing the threshold because we see Athena the mentor, Penelope his wife and reward also the people being mad is the crossing back to his original world.