
Previously on
The Big Bang Theory...
The Big Bang Theory Season 12, Episode 18

♪ That all started
with a big BANG ♪
The Big Bang Theory Season 7, Episode 16

♪ That all started
with a big BANG ♪
The Big Bang Theory Season 5, Episode 2

♪ Bang! ♪
The Big Bang Theory Season 7, Episode 15

# That all started
with a big BANG #
The Big Bang Theory Season 11, Episode 8