You should watch:

The Emissary

This was episode number 20 of season 2.

The following characters appeared in this episode:

(as Dietrich Bader)Tactical Crewman

(as Lance Le Gault)Capt

(credit only)Wesley Crusher

(as Anne Elizabeth Ramsey) Ensign Clancy

(voice) (uncredited) Enterprise Computer

Admiral Gromek

Captain Jean-Luc Picard

Chief Miles O'Brien

Counselor Deanna Troi

Commander Wiliam T Riker

Doctor Pulaski

K'Ehleyr

Lieutenant Geordi La Forge

Lieutenant Worf

Lt Commander Data