Poisoned Blood (Adopted from Poseidon'sWizardingGuardian)

Remus Lupin, werewolf, smart, resilient, and shy. Suddenly sick. Horribly sick. Diagnoses? Poison. A new poison, one that is in no book, is now in his bloodstream. Chances of survival are slim unless James, Sirius, and Peter can somehow work together with Snivellous, oh, sorry, Snape, to find the antidote. No slash, takes place in the Marauder's fourth year.