My thinking got to... Cast = catch, not is part of the word as it is caught in it, but that leaves an explanation for the 'r'. That gives contrast, which is 'set off'.
Contract could be bookless if you take off 'tract', but then how is 'con' related to either cuba or cebu?
And then how does contract come out of clue for 31a?
Maybe it's something completely different!
Thanks.