As a result of the success of "Buffy the Vampire Slayer", Whedon was given the opportunity to make "Angel", his 1999 spin-off series of the show. David Greenwalt and Whedon collaborated on the pilot which was going to be developed for The WB Network. During the series' early expansion, efforts were made by the network to mitigate Whedon's original concept. "Corrupt". A precociously optioned second episode was entirely abandoned due to the gloominess written into the script. The tone was then softened in the opening episodes, establishing Angel Investigations as an idealistic, shoestring operation. It follows Angel, who works as a private detective in order to "help the helpless".