In the season four finale, Penny and Raj bond and after having a lot to drink, they end up sleeping together. Later, Raj reveals to Penny that they were about to sleep together when she instantly asked if he had had protection. He had trouble putting it on, and she tried to help, ...
As Leonard, Howard and Raj tried to locate Bitcoin they had mined years before, which were now more highly valued, they turned to Penny to find Leonard's old laptop that he gave to her. After Penny admitted that she had given it to Zack, the pair went to him to try retrieve the la...
Their friendship eventually becomes strained when Leonard begins dating Raj's sister Priya and gets worse when Priya forces Leonard to cut his ties with Penny permanently. During their time apart, Penny becomes very close to Amy and Bernadette, who provide comforting support and help her understand...