Season 1 - Episode 2. First aired on Wednesday, April 12th 1978.
(also released as "Spider-man Strikes Back")
Read the full plot.
Spidey saves himself from his death-dive by forming a net with his webbing. But in the confusion, White and Angel escape with the plutonium.
Jonah Jameson, owner of the Daily Bugle, discovers that White has fled to Los Angeles and arranges for Peter Parker and Gail Hoffman to travel to the west coast in search of White.
White is demanding one billion dollars in return for not setting off the plutonium bomb in a heavily populated area.
The authorities assume, wrongly, that he means New York. In fact White plans to set off the bomb in Los Angeles at the time the President is giving a speech there.
Spider-Man finally tracks White to his lair and learns of White's plans. He locates the bomb and defuses it at the last second.
White escapes, vowing that he and Spider-Man will meet again. (They don't... - Paul)
[Summary from UK 1982 Spider-man Annual]