This is season 1, episode 4 and 5 of the 1976 Wonder Woman TV series.
The plot revolves around the Nazi's trying to figure out the source of 'feminum', the metal that Wonder Woman's bracelets are made out of.
The episode features Diana's younger sister Drusilla, played by Debra Winger.
The episode climaxes with Nazi Captain Radl kidnapping General Blankenship, and setting up a trap for Wonder Woman. Drusilla figures out where the Nazi's are hold up, and decides to transform into the beautiful Wonder Girl. Young and naive, Wonder Girl confidently walks into the Nazi trap.
Wonder Girl begins fighting the bad guys, and is doing quite well. She is able to throw some bad guys around the room, before someone distracts her. Wonder Girl loses focus, and Captain Radl is able to chloroform her from behind. Wonder Girl puts up a valiant struggle, but the chloroform does the trick and puts her to sleep. She faints to the ground while the Nazi's look on.
Wonder Girl is taken to an abandoned warehouse. When she wakes up, she learns that the Nazi's intended to kidnap Wonder Woman instead. Drusilla pretends to be Wonder Woman, in order to plan her escape.
In part 2 of the episode, Peter Knight pretends to get betrayed in order to gain Wonder Girl's trust. Captain Radl fires a gun at Peter, only for Wonder Girl to deflect the bullet with her bracelet. Wonder Girl is nearly able to escape, but one of the Nazi's quickly chloroforms her from behind again.
The episode also depicts several Amazon warriors and Wonder Woman knocked out with sleeping gas.
One of the greatest episodes in Wonder Woman history, and a classic for sleepy fans!