Halloween night finds the ER awash with allergic or otherwise incapacitated children. Kerry tolerates a visiting candidate for chief while she waits for the official vote. Romano operates on an 11-year-old girl and finds shes genetically male. Carter leaves Lucy in charge of a dorm party hes supposed to be overseeing, with unfortunate results. Mark learns that Jenns moving to St. Louis--with Rachel. Mark and Carol treat a pregnant schizophrenic.