Jennifer Love Hewitt on 'Ghost Whisperer''s Last Episode

Melinda's (Jennifer Love Hewitt) investigation of a poltergeist in the hospital leads to a showdown with supernatural forces terrorizing her and her son on tonight's "Ghost Whisperer."

"We have lots of strange children marching around in scary masks, which is so creepy," Jennifer tells ET. "It's like, 'Why do we always have to make children creepy?' I'm constantly asking the producers. I'm like, ''Can't we just have a child who's not creepy, because it freaks me out. It gives me nightmares and I don't like it.'"

There actually is a non-creepy kid on "Ghost Whisperer," and that is her son Aiden (Connor Gibbs).

"We find out that he has to come to Melinda's aid and really saves her life in the season finale," Jennifer says. "The dark side gets extremely powerful very quickly and he's sort of her only heroic key. So my son gets to kind of be a superhero for the episode, which is very cool."

The "Ghost Whisperer" season finale -- possibly the series finale -- airs tonight at 8 p.m. on CBS.