Deep Dark Valley is the name of a song that plays in "Where's Mama Hook?", where Mama Hook is given the wrong map by Mr. Smee and instead of going to Peaceful Valley, she is headed off to Deep Dark Valley.
There's a place where pirates fear to tread
But I'm afraid it's dead ahead
'Cause Mama Hook went there for tea instead
Smee: Oh no!
There be creepy creatures creapin' about
And once you're in, you'll never get out
Sharky: Oh, matey please don't say we have to go
to Deep Dark Valley
Bones: It's more than I can take
Deep Dark Valley
Sharky: Just to say it gives me shakes
The legend of Deep Dark Valley