Biosquare Hey Arnold! : Season 3 Episode 33
TV-Y7 Nickelodeon 15m
Aired: December 28th, 1998 @ 6:30 PM EST on Nickelodeon
Helga and Arnold locked in a greenhouse together for 24 hours? Now THERE'S a science fair project! They should both get a great grade on it - if they don't kill each other first.
