The choice of the right door does not seem to matter here below, because you get through every exit in the confusing cave system. I find one pirate hook on a skeleton (how it gets here?), which I take immediately. On the end of the many corridors i get in the part of the newer canalisation under the place of the library. Here branches the corridor in a room in which a coffin is located. Sadly the room is separeted through a grid with a rusty lock which I can't open.
After it took a long time until I have understand, how I can free the torch out of the muddy crust, I naturally want it and pull it. Well, the classic happens: it is a trap door. And the next level of the cave system is awaiting me.
The ladder in the next room that I reach leads me upstairs in the room with the floor plate with which you can not do anything else. Okay, back downstairs and go on. I get to a bridge in the underground over which a wooden stopper can be seen which I already have seen a level upwards. But I take care on it later.
After the bridge is only one room with inscriptions in it. The inscriptions describe the appearance of the grale as in my father´s diary. I come to the conclusion that either the manuscript from al-Musafir or the letter from Staubig about the book Merlins have the correct description of the grail.
To wait with the stopper was the right decision, because after I loosening him up with the hook and my whip, all the water is flowing down from the underground sea and destroys the bridge. Thereupon I go upwards and now I can advance through the drained sea in the next cave system.
There I get into a room with a wooden machinery. The machine is missing a rope that I replace with the red cord from the library and get the machine going. Something is rumbling somewhere.
With the three wooden statues I come after a little thinking behind it that maybe in the grail diary of my father something could be written. And how! The right combination of the statues opens up the door to the next to it. I am discovering a wooden bridge which I can bring in the right position with the machine I have repaired and get to the next closed door. Their opening mechanism is also explained in the diary and also a simple sound puzzle, which I can solve with the skulls in front of the door.
I am at the mysterious coffin! From the other side of grid! I open the coffin and find the second hint of the crusader. The town Alexandretta is mentioned on their ruins the town Iskenderun is build. There should we find finally the grail.
I climb out of the cave system and am expected by Elsa Schneider, who already has already searched everywhere for me, meanwhile Marcus has discovered where my father is. He is being held at Brunwald castle on the border between Austria and Germany.