The day Dr. Sobel (Billy Crystal) finally gets married with Laura (Lisa Kudrow), Jelly (Joe Viterelli) crashes in and hauls Dr. Sobel off to the meeting of the big crime bosses.
While at the meeting, a debate between Sobel and Primo Sindone (Chazz Palminteri) ensues, and when Primo is about to shoot the doctor, in comes Paul (Robert DeNiro) and stops him. Then, he announces that he has the intention of quitting the mob life, and retire peacefully. Everyone agrees and bids him farewell; however, Primo and Carlo (Leo Rossi) -who happened to be the one who tried to have him killed while in Miami, earlier in the film-, step out and try to kill Paul; a colossal shootout takes place, during which the cops and the FBI arrive and arrest everyone. Dr. Sobel is shot when he catches a bullet fired by Primo intended to hit Paul, but paramedics assist him during the bust.
Paul is sentenced to 18 months in Sing Sing, and Primo is known to have been found dead somewhere close to LaGuardia Airport.
In the end, we see Dr. Sobel and Laura, dancing and cavorting together at the front porch of their house, while Tony Bennet (himself, of course!!) sings to them.
Thanks Dr. Mat!