Adicia, now turned into a tiger, is much better off removed from the world of men.
And now that the evil Souldan is also out of the picture, Arthur and Artegall spend a little time in his former castle before heading out with Samient to see Queen Mercilla.
On the way, they begin to chat about this and that and Samient tells them about a villain named Malengin terrorizing the land. He's very crafty and deceives and robs everyone.
He lives deep underground, no one knows how far down, and no one is able to find him.
When Artegall and Arthur hear about this man, they want to find his residence so Samient agrees to take them there.
At the entrance to his cave, they have Samient go close and wail loudly in order to coax Malengin out.
This works, and he emerges. He's very ugly and carrying a large hooked staff and a net.
Samient is quite concerned when she sees him and begins to very genuinely call for help.
But Malengin begins to try and calm her down and win her over with his deceptive smiles.
Once she is distracted, he throws his net around her and takes her to his cave.
However, Artegall and Arthur are there blocking the entrance and when he sees them standing there, he panics and run away.
Artegall immediately pursues him but Malengin is a tricky one to catch: darting from rock to rock between small passages he turns into a fox, next into a bush, then into a bird.
But Artegall knocks the bird down with stones and then grabs Malengin so he won't run away.
But Malengin turns into a hedgehog, prickling Artegall (who drops him). But Talus grabs him and throttles him so hard he breaks all his bones. Then he leaves him for dead.
They then arrive at the castle of Queen Mercilla, and Artegall and Arthur are amazed at its beauty. They see the queen's giant porter named Awe, who guards the hall. They are ushered in by Order, who commands the hall.
Everyone is astonished to see the knights, since there is no war or violence in that hall and therefore they aren't used to seeing armor.
When they enter, a sentence has just been passed against a bad poet and his tongue has been nailed to a post. Ugh!
Above him hangs a sign that says "Bon Font," but with Bon crossed out and Mal instead written over it—this is the poet's punishment for producing slander against the queen.
Finally, they arrive at the great hall of the queen and see her sitting in majesty on a great and high throne looking like an angel on a cloud with a sword at her feet.
Around her are a group of virgins, daughters of Jupiter called Litae, who offer help to princes and ask for mercy for suppliants.
The queen is also flanked by a lion.
The two knights come before her, bow low with great respect, and she recognizes them with grace.
As it so happened, the knights have arrived right when the queen is judging an important case.
A woman, the infamous Duessa (from Books I-III) has been brought to trial and charged with all kind of infamy, despite that fact that on the outside she looks beautiful and modest.
She has been charged by a man named Zele. He has outlined her various offenses: deceiving knights, conspiring with Paridell and Blandamour against Mercilla, and many, many other crimes.
Then a man named Kingdoms Care also speaks against her. Then Authority challenged her and the laws of Nations denounced her. Some dude named Religion condemns her and finally Justice charges her with breaking the law
In response, Pity comes to plead for her, as does Regard of Womanhead, Danger, Nobility, and Grief.
Arthur, being naturally disposed to compassion, began to feel bad for Duessa, but soon Zele returned to attacking her and this time brings the witch Ate with him as an example of her companions, and also brings forth Murder, Sedition, Incontinence, Adultery, and Impiety.
After seeing these, Arthur no longer feels bad for her and it is time for Mercilla to give her judgment.
While Mercilla understands that Duessa is guilty, she also feels pity for her… and the canto ends on this ambiguous note.