Board Thread:Spoilers!/@comment-25551215-20160315233708/@comment-26443838-20160811231546

No, the dark secret for Charming seems different. It was teased that he will learn something that was not true what he believed which will affect his relationships with some people.

They also teased that Hook had a dark secret which will affect his relationshops, and some people believed that it might have something to do about Charming's father and where he might get involved. None was confirmed, but it seems close enough until then.