Sealed with a Kiss

Erica meets an older guy at the school dance and french kisses him in the school stairwell. She later feels ill, and thinks he may have given her mono. When he drops by the house to visit, Erica is too sick to go out. He asks her twin sister Heather to go for a drive instead, where he kisses her as well. Heather tells Erica what happened and they both go to the doctors office to see if they have mono. They are both relieved to find out Erica had just come down with the flu.