Okay, so I'm trying to do the Dark Brotherhood quest where you have to assassinate Gaius Maro. For the quest bonus you have to kill him in another town... fine. Problem is, the guy is not moving... at all. At first I thought I had to stalk him all the way to the city... nope. Not moving. Then I thought, okay... I'll ambush him in one of the towns he's visiting. Nope, not coming. I have the schedule for his route but he's just not moving. I was waiting in Riften the entire day but he didn't show up. Is this a bug or have I missed something?

PS: I am playing on the PC.