Shrooms - Unseen Edition

A group of American students get a lot more than they bargained for when they ingest some magic mushrooms during a trip to Ireland. Although they're under the impression that they've acquired the best hallucinogenic money can buy, it's not long before they're convinced there's something sinister lurking in the woods nearby. Is there something picking them off, one by one? Or have the mushrooms begun to have an effect on them? Either way, it's the trip from hell, and it's a long time till morning...