Tick Tock Tick Tock

I need a plot device.
A plot device for a narrative poem.
A MacGuffin.
That's what Hitchcock called it.
He used it in his films.
Something the story revolves around.
Alfred Hitchcock the Master of Suspense.
The director of Psycho and The Birds
If it worked in his early films.
It'll work in a poem.
But what can I use for my plot device.
My MacGuffin.
Something to make it tick.
That's it.
A ticking bomb.
Think of the suspense.
The drama.
A race against time,
For a hero to find and defuse with seconds to spare.
And then he gets the girl.
Yeah that'll work.
If it's good enough for Alfred Hitchcock.
It's good enough for me.
I'll call it The Ticking Bomb.
No.
Too crap.
The Bomb That Ticked.
Oh dear God no.
Even worse.
Too amateurish.
Need something better.
Something classier.
Something simple.
Something catchier...