@mg = qw(Sam sat on the ground and put his head in his hands.  'I wish I had never come here, and I don't want to see no more magic,' he said, and fell silent.);

## standard way
# create a new array and assign back into place

@mg = map ucfirst, @mg;

# OR...

## work in place
# alter existing array
$_ = ucfirst() for @mg;