Several French lords prevail upon Bertram to let them prove that Parolles is a scoundrel unworthy of his company. They will set Parolles up to recapture a drum which he lost in battle (a military disgrace), then they will capture and blindfold him, and in Bertram's presence, they will get him to "betray you [Bertram] and deliver all the intelligence in his power against you." Bertram agrees to the plot. Parolles enters and takes the bait:
Parolles: I know not what the success will be,
My lord, but the attempt I vow.
Bertram: I know, thou'rt valiant; and to the
Possibility of thy soldiership will subscribe
For thee. Farewell.
Parolles: I love not many words. [Exit]
First Lord: No more than fish loves water.
Is not this a strange fellow, my lord,
That so confidently seems to undertake this
Business, which he knows is not to be done,
Damns himself to do, and dares better be
Damned than to do it? (86-97)
Bertram ends Scene 6 asking a lord to intercede for him to "the lass I spoke of" (Diana).
Helena, for her part, bribes the Widow of Florence to help her convince Diana to allow herself to be used as a decoy in trapping Bertram. Helena wants Diana to, first, get the Count's ring in exchange for the promise of future favors, and then to set up an "encounter" with him.
In fine, delivers me to fill the time,
Herself most chastely absent. After,
To marry her [pay her dowry] I'll add three thousand
To what is past already. (33-36)
A "noble" Count (Bertram) agrees to entrap a friend, and a "chaste" maiden (Helena) offers large sums of money to a mother to get her daughter to arrange to have sexual intercourse with a legally married man. The plot now grows murky in this unusual "comedy." As Parolles is himself dishonest, however, there is a kind of justice in ensnaring him: the trickster will himself be tricked. Yet Bertram himself (like Parolles) seems disloyal. A similar parallel exists in Shakespeare's Henry IV, Part 1, in which Hal's delightful scoundrel-companion, fat Jack Falstaff, is exposed publicly as a coward for the good of young Prince Hal. The difference, of course, is that Hal has known all along what mettle Falstaff is made of, and Hal himself is of enormously greater stature than Bertram. Bertram is petty by comparison, as is this scheme to expose and tease the loathsome Parolles.
Helena's plan also has a darker element, for she does have the matter of "right" on her side:
Helena: Why then tonight let us essay our plot,
Which, if it speed, is wicked meaning [Bertram's]
In a lawful deed, and lawful meaning
In a lawful act [Helena's]
Where both not sin, and yet a sinful fact.
But let's about it. (43-48)
Helena undertakes the adventure with relish, and she paves the way with purses of gold to the Widow of Florence and her virgin daughter, Diana. The quoted passage captures all the ambiguity of the plot — Bertram will be making love to Helena, his rightful wife, though he thinks that she is Diana, an attractive virgin whom he fancies. His intention will be sinful, although the act will be lawful. "Ethics be damned!" seems to be Helena's attitude, so long as "all ends well" and is just.