Adventure Hook: Seedlings

Strange trees with strange fruit have popped up everywhere in town over the past several days. At first, they were just small shoots jutting through the cobblestones and open markets of the area, but in just a few days they have grown to full-sized trees complete with fruit. Anyone brave enough (or stupid enough) to eat the fruits appear to fall into a coma within a few hours of eating the tasty red morsels, but seem to suffer no ill effects other than the inability to wake up. Where did the trees come from? What is going on with the fruits? How will the PCs get the innocents out of their comas? Answers lie in whatever devious minds of the GMs that wish to pick this up and run with it.