What are the keywords of the episode which received the 2nd-highest number of votes?
the 2nd-highest number of votes refers to second max(votes)
SELECT T2.keyword FROM Episode AS T1 INNER JOIN Keyword AS T2 ON T1.episode_id = T2.episode_id WHERE T1.votes NOT IN ( SELECT MAX(T1.votes) FROM Episode AS T1 INNER JOIN Keyword AS T2 ON T1.episode_id = T2.episode_id ) ORDER BY T1.votes DESC LIMIT 1