Subquery with too many columns

SELECT m.from_user_id,
       m.message,
       m.send_date
FROM message m
WHERE m.conversation_id IN (
  SELECT cu.id,
         cu.conversation_id,
         cu.user_id,
         au.username
  FROM conversation_user cu
  INNER JOIN auth_user au ON cu.user_id = au.id WHERE conversation_id IN
    (SELECT conversation_id
     FROM conversation_user
     WHERE user_id = 32)
  AND user_id != 32
)
ORDER BY send_date DESC LIMIT 1;