I really need to stop visiting Riften at night. I'd just gotten off the cart at around 2 am when Serana was hit in the face by a ball of poisonous phlegm. A single bolt took out the giant spider that had come up from the forest to say hello and we headed back up towards the gates only for a dark brotherhood assassin to come running in from the east. He was quickly taken out with some help from the nearby guards and after quickly looting his valuables we proceeded into the city.
We started walking up towards the inn, when from behind us came "Ha! I found you!", a group of vampires had come in through the gate. Serana promptly got into a "ha! I steal your lifeforce." "No, I steal your lifeforce" duel with the ancient vampire while the guards jumped on the blooded vampire. This left the fledgling coming at me who went down with a bolt to the face and I started moving around close to the gate to get a shot on the vampire the pair of guards were fighting. As I was taking aim, suddenly I was staggered and lost a big chunk of health as someone yelled out "You never should have come here!". Behind me from nowhere a bandit plunderer had appeared and was hacking away at me with his greatsword. Cutting a hole in time to swig some healing potions and a couple of bolts took down the bandit, so I turned to assist against the remaining vampires.
The pair of guards had managed to take down the vampire they had been attacking and were moving in to help Serana deal with the ancient vampire she had been playing life swap with. I took a shot to stagger the vampire when I heard the faint sound of fire magic roaring. I turned and looked down the street to try and find who was casting magic, when I saw perched atop Black-Briar manor a legendary dragon happily toasting the rest of the city guards. Quickly finishing off the vampire we then had to go on your typical, run around the city getting shots off at the dragon when buildings don't get in the way hunt. Eventually it was forced to ground badly injured next the the shrine of Talos where Nura Snow-Shod had been ignoring all the commotion and had remained there praying. I thought we were about to loose a named npc when the dragon snapped at her, but she got up went "lol, no" and electrocuted the dragon to death.
All I wanted was to get a bed for the night so I could sell my loot in the morning. Definitely not visiting at night again.