Following a heated argument with Sheldon over the thermostat, Leonard seeks refuge in Penny’s apartment. While there, he recounts the story of how he first met Sheldon seven years earlier (2003) and why he continues to live with him despite his difficult personality. The Staircase Implementation | The Big Bang Theory Wiki
" The Staircase Implementation " is the 22nd episode of the third season of , which originally aired on May 17, 2010. The episode is best known for providing the "origin story" of the main group through a series of flashbacks. Plot Summary The Big Bang Theory 3Г—22 : The Staircase Implem...