Massinger's protagonist, Hortensio, has been characterized as "a sort of pale Quixote; a knight-errant a little cracked or crazed; very sincere, and a trifle given to uttering vague and useless professions of hyperbolic humility and devotion.
The opening scene, however, deals with love rather than war: a love-sick gentleman who calls himself Hortensio is hanging around the Mantuan court, wherever he can catch sight of the princess Matilda.
In the process, the Florentine officer Alonzo is seriously wounded, and falls into the care of Octavio, a former Mantuan general and courtier who lives retired in the country after losing the Duke's favor.
(Octavio at one point masquerades as a monk to help Alonzo "cure the ulcers of his mind," to overcome his depression and mental distress – a feature typical of Massinger's dramaturgy.
Duke Lorenzo, talking among his officers, admits that his prior demand for Matilda's hand was a feint of ambition, and that he has no real interest in her, or in a marriage of state.
The princess's beauty and her noble character work a change of heart upon Lorenzo: he renounces his military conquest and returns Mantua to Gonzaga's control.