1x19 - Saved by the Bell: The College Years

As Zack and Kelly make plans for their wedding, they get a surprise visit from their old friend, Lisa Turtle. However, since Alex and Lesley also want to be Kelly's maid of honor, the competition between the three of them ensues. Meanwhile, Slater doesn't approve of Zack's decision and turns down his offer of being the best man. Screech agrees to take his place with predictable consequences.