Sherlock said to Watson: Eliminate the impossible and whatever remains - however improbable - must be the truth. (The trick, of course, is finding out what's impossible.) Normal sudoku rules apply. Digits along palindrome lines read the same forwards or backwards. The digits in a cage must sum to the small clue in the top-left corner of the cage. Orthogonally adjacent cells do not sum to either 5 or 10.