Batman's call to adventure is when the joker reveals himself and he says that batman has to expose his true identity or people will die. Bruce has to make the decision to wether or not to expose himself risking his life and possibly loved ones or save others from dying.
In this movie I believe that Batman has two mentors or people that help him. This would be Lucifer and Alfred. Alfred is important mentor because he gives batman advice and encouragement while Lucifer makes Bruce cool gadgets.
Seizing the Sword
Batman crosses the threshold when the Joker crashes Bruce's party. The jokers intention is to capture Harvey Dent and draw out Batman. This is where batman has his first encounters with the Joker and it turns into a fight.
I believe the ordeal in the Dark Knight is when Harvey and Rachel are locked in warehouses wired to oil drums. Batman has to choose who he wants to save and in the process he losses Rachel when the Joker switched the dresses. They also lose Dent in a way because this is when he turns bad.
I think Batman seizes the sword whenever he defeats the Joker and proves to him that there is still good in Gotham. He proves this when the crooks and innocent people of Gotham are given an ultimatum given by the Joker. The Joker led them onto two ferries and gives them the detonator and tells them to choose who gets to die.
The Return in the Dark Knight is when the people of Gotham are safe and Batman goes back into his secret cave. Until the next villain comes to Gotham and Batman has to come out of hiding and save the day.