Smallville: Season 5, Episode 4

5 - 4: Aqua

A summer beach party at Crater Lake takes a dramatic turn when Lois hits her head while jumping into the lake. Before Clark can save her, a mysterious swimmer, Aquaman, a.k.a. AC, comes to her rescue, out-swimming Clark and leaving him baffled. Meanwhile Professor Fine tells Clark that Lex is behind a covert operation manufacturing weapons. AC attempts to break into the Luthercorp Marine Center in an attempt to destroy one of Lex's torpedoes and is captured by Lex...