13-year-old Laurie (Lauri Hendler, 'Gimme a Break!') is visiting the Ropers; the daughter of a friend of Helens', she's lonely & depressed due to her mother re-marrying and being off on her honeymoon. When Laurie visits the kids, Jack manages to charm her out of her depression, only for the young girl to immediately develop a crush on Jack! Jack has to try to convince Laurie that no relationship between them could possibly happen, while also trying to get it on with a potential conquest, Rita (Lois Hamilton, "Summer Rental").
As part of the hilarity, Laurie has resorted to sneaky measures to get Janet & Chrissy out of the apartment, and they of course assume Jack was the culprit upon learning of Ritas' existence.
There are some good, solid laughs throughout this decent episode, with young Hendler proving to be annoying in an utterly priceless way. (That's a funny image of her peering through the window.) In general, this is another prime vehicle for the talents of John Ritter, as he gets to be funny, charming, and also sensitive towards this impressionable child.
Overall, 'The Crush' sizes up as more highly amusing 'Three's Company' hijinx.
Seven out of 10.
