Beginning with the letter A at the top of the diamond, descend word by word to reach two 11-letter anagrams in the middle. Each word in the upper half contains all the letters of the word directly above it, PLUS an extra letter, shown on the right. Then, continue your descent to reach the letter E at the bottom of the diamond. Each word in the lower half contains all the letters of the word directly above it, MINUS one letter, shown on the right.
A correct answer will reveal in the right-hand column the extra letter to be added to the next word.