If your after an original plot though, how about:
A) A group of the village kids go missing. Some detective work on the PCs part shows that they went to the old cairn on the hill to play a 'magic' game. They intoned ancient folklore, like the horror games that kids play these days. Like saying "bloody mary" in the mirror etc.
The kids are gone though. Some religion/arcane shows that some of the elements of the game could have some actual ritual power. The cairn on the hill is almost certainly a link to the Shadowfell.
The PCs re-enact the kids 'game' and travel to the Shadowfell to try and save them. As this is a low level adventure, maybe the kids were not taken by some barrow-king or anything like that. They just had mist come up around them and it grew cold. They got scared and ran off in different directions, trying to run home.
So the PCs have to search through a particularly foggy area of the Shadowfell to try and find the missing kids before something sinister does. The kids likely split up or got separated, each has a clue about where the others might be. So you have the option of making this as long or as short as you want.
Ever played the computer game Limbo? If not just look up a little clip, it might inspire the imagination a bit.
B) The PCs village is attacked by something well and truly outside their level range. The BBEG comes through and using magic or a cursed sword simply rips the souls straight out of the body of those that defy him. The PCs fall victim to him, they watch helplessly as their still breathing bodies are left behind and they are plunged into the Shadowfell.
The PCs are still alive in the real world, but soulless, just sitting there, not even feeding themselves. The PCs in the Shadowfell play as souls that must escape back to their bodies.
The Raven Queen has no authority over them, as they are not dead and are not meant to be there. So some of her people might even be helpful, unlike normal where they would jealously guard the souls of the dead.
The PCs go on an adventure to find the nearest crossover point between worlds and find a guide to help them do so.
Finally they make it back and you have established a BBEG for them to fear and revile. Maybe the Raven Queen even takes exception to the BBEG breaking the rules and doing what he did...