
Sorry, guys, but Secret Agent
Laser Obstacle Lunch is just stupid.
The Big Bang Theory Season 2, Episode 18

Again, I'm sorry,
I shouldn't have kept it a SECRET.
The Big Bang Theory Season 9, Episode 20

You know I can't keep a SECRET.
The Big Bang Theory Season 4, Episode 6

Your soul is... It's like a SECRET
that I never could keep.
The Big Bang Theory Season 10, Episode 13

Because, uh, Batman has the SECRET.
The Big Bang Theory Season 4, Episode 6