Alundra's adventure begins on the Klark, while it is worth talking to everyone in order to learn what is going on and general backstory, the only people that have to be talked to are the two sailors in the room opposite Alundra's Cabin, in order to reach them, head through the top-left door. They mention the nightmares Alundra has been having and the crack between Alundra's cabin and this room, which will come in useful.
After this, head through the bottom door and talk to Captain Merrick, who then heads upstairs in order to steer the ship. Talk to him again and he will advise Alundra to head to sleep. Head to Alundra's cabin, which is the top right door, and Alundra will automatically go to sleep. A dream sequence will occur between Lars and Melzas.
Once Alundra wakes up, the ship will be shaking and the door leading out of Alundra's cabin will be jammed shut. In order to get out, walk through the much wider crack connecting the two rooms and throw the crate aside, then exit through that door.
A sequence will automatically play in which the ship will split it in half, before the screen fades to white.