Plot summary from IMDB.com:

While driving home during a rain filled night, straight-laced lovebirds Brad and Janet, by chance, end up at the castle of one Dr. Frank-N-Furter and his strange and bizarre entourage, and find that he's having a party. This is no ordinary party, no ordinary night. This is the unveiling of the Dr's latest creation: Rocky; A man-made Adonis that will give...absolute pleasure. This is an exceedingly grand visual and musical camp satire of the golden days of the B-movie horror and science-fiction genres. Projected along with a musical soundtrack to give "audience participation" a new meaning in dimension, time and space, this shall be a night that both Brad and Janet will remember for a very, very long time in the sexually kinky, rock 'n roll (f)rock-opera world of a gender-bending scientist...and his time warped plans