As the small group of mercenaries settled down for the night, they failed to notice that some small pieces of barbed wire sticking out of the ground nearby were moving like tentacles.Until it was too late and they woke to feel it clutched around their throats and squeezing hard. As their blood spilled upon the ground the Barbed Arms had claimed yet more victims.
When running a new party, get around the question of plot density by having the first discovery to be a deck of fate, or whatever you call it. If you use a real deck, you should definitely stack it to have the desired outcome, which is to curse the party to attract weird things to happen and involve them. This should not be told to the players at the time, so that they won't just up and try to get themselves 'decursed'. Though quite why they would want to is beyond me.