Death House

From introduction:

You can run Curse of Strahd for 1st-level characters with the help of this optional mini-adventure, which is designed to advance characters to 3rd level. Before the characters can explore the haunted townhouse known as Death House, you need to guide them to the village of Barovia. The “Creeping Fog” adventure hook in chapter 1 works best, as it introduces few distractions.

Once the characters arrive in Strahd’s domain, steer them to the village. For the duration of this introductory adventure, any attempt by the characters to explore other locations in Strahd’s domain causes the mists of Ravenloft to block their path.