t is Sir Sidbury, who bears the blazon "Azure, a unicorn head argent." He is suspected of being part of the plot. "Run to the stables and stay there," your father says, "until I can get him to leave." Sir Sidbury tries but cannot persuade your father to join the plotters, although he is careful not to say that he will help the King against them, either. You look forward to spending an uncomfortable night in the stables.
     Before Sir Sidbury leaves, a watcher on the tower spots another man on horseback in the distance. If he is a knight in alliance with Sir Sidbury, the two of them together might try to take over your father’s castle. On the other hand, if the knight is an ally of the king, Sir Sidbury might learn more from the new knight than your father wishes him to know.
     The watcher on the tower reports the blazon down to you in the stables (your father is busy talking to Sir Sidbury, being very polite and saying very little).

The blazon the watcher reports is:
Vert, a castle or

Click on the shield that matches the blazon.
Be careful!

Read Roger the Herald's Notes on Blazonry for Beginners