The Crown Prince isn't a great guy, and we hear stories of murdered girlfriends and that he is planning to take the crown from his aging father, so we support the plot by Eisenheim and Sophie to run away together - but first they need a plan.
Inspector Uhl informs Leopold that the two have met in secret. The Crown Prince gets drunk and makes a scene one night, accusing her of all kinds of stuff and she screams as her white horse whisks her away. The horse returns the next day with blood on its neck and after a huge search by the city's residents her body is found by a stream in the woods by Eisenheim. But he cannot revive her, and she has already passed away.
The Inspector wants to see the body - its clear that she is dead, although the physician is acting a little funny.
Eisenheim withdraws himself to work through his grief alone. In time he opens a new theatre and starts a new kind of show with Chinese guys, smoke and mirrors. Basically the crowd pays to see him walk on stage, sit on a stool and then summon a 3D spirit to answer one or two questions before they leave, happy with the result. He's onto a winner.
Leopold wants Eisenheim arrested. The Inspector tries to get him on fraud charges, but Eisenheim explains that it is all an act to the crowd and walks free.
Next time on stage, the spirit that returns is that of Sophie - Eisenheim doesn't say a word but members of the crowd accuse the Crown Prince of her murder. Uhl speaks to Eisenheim after the show, and tells him of his respect for his work, but that if he summons the spirit of Sophie again he'll have no choice but to have him arrested.
The next night, the theatre is packed again. Eisenheim walks out onto the stage and takes his seat and summons .... Sophie. The audience gasp. Those in the crowd who accuse the Crown Prince of murder are taken outside. Uhl gets onto the stage and tries to arrest Eisenheim - but his hands fall through his body, it is all some type of 3D video show.
The cops snatch the little Chinese guys who know nothing. Then the Inspector starts to think about stuff and goes to the stables where he finds another jewel from the Crown Prince's royal sword.
With the evidence he needs, he goes to Leopold's Royal quarters. Leopold cannot believe what is happening, and decides to take his own life.
Outside the palace, his pockets are picked before a little kid runs to the Inspector and hands him a parcel - inside is a bunch of papers revealing the secret to "The Orange Tree" act he liked the most. Uhl then spies Eisenheim in disguise and gives chase - but loses out when the magician gets onto a train just in time. Standing at the station, Uhl then slowly starts to piece everything together -- a drug put into Leopold's drink to make him drunk, the fake blood, Sopie was just pretending to be dead, the physician was also a friend of Eisenheims and so on. Rather than anger at his future career down the toilet, he just gives out a little laugh.
As it ends, Eisenheim approaches a little wooden cabin where he meets with his new fling. I hope it was worth all the effort!