The frenetic and hilarious fourth chapter of this comedic masterpiece kicks off with Pampinea reigning supreme, her every utterance hanging heavily in the air as she revels in her newfound status as the bearer of Leonardo's unborn child. Her authoritative demeanor, however, doesn't sit well with the rest, and tensions simmer as Tindaro courageously confronts her, much to the chagrin of his fiancée, Licisca.
Meanwhile, Dioneo, ostracized from the group for his treachery against Tindaro, sits in solitude, a distant figure shunned by his former companions. Frustrated by his isolation, he seeks solace in Neifile, who frantically chews on rhubarb in a futile attempt to purge her sinful desires. But Neifile's revelation that she no longer harbors affection for him, knowing his true nature, leaves Dioneo unfazed. He scoffs at her rhubarb ritual, suggesting a more practical cure: a tryst with her husband to quell her lustful thoughts.
As Pampinea's burgeoning belly betrays the passage of months since their retreat to Villa Santa to evade the plague, Panfilo and Sirisco find themselves growing restless. They chafe at Pampinea's presumption of dominion over the villa, a privilege she does not rightfully hold. Yet, they devise a scheme, and soon, a rowdy cavalcade arrives, led by Leonardo's cousin, Ruggiero, and his entourage of revelers. Their boisterousness and penchant for debauchery clash sharply with Pampinea's refined sensibilities.
Ruggiero, with a roving eye for the ladies, makes himself comfortably at home, ordering wine to toast his arrival. The festivities spiral into chaos as Neifile, her own desires awakened, finds herself drawn to these new arrivals, much to her husband's dismay. Pampinea, unimpressed by her uninvited guests, attempts to usher everyone to their chambers, but the party has barely begun. Ruggiero, undeterred, leads the revelers to Leonardo's secret chamber, a lurid den adorned with phallic symbols and a discreet 'whore door,' leaving all in stunned disbelief and Pampinea reeling in horror.
As the raucous revelry, fueled by the flow of wine, raged unchecked within the confines of the secret parlor, Tinardo found himself unceremoniously deposited in the kitchen of the villa, another of his spurious ailments claiming him as its latest victim. Cook Stratilia, devoid of empathy, greeted him with a barrage of insults, which, given Tinardo's fragile constitution, proved to be a harsh blow indeed.
Meanwhile, upstairs, Panfilo and Sirisco grappled with the gravity of their mistake in inviting Ruggiero to their villa. Though he might indeed be the rightful heir, Ruggiero proved to be a veritable nightmare, threatening to drain the villa's stores of alcohol dry amidst the raging pestilence outside its walls. With no hope of replenishing their supplies before the plague's passing, their situation grew dire.
Within the parlor, the festive mood swiftly turned tragic as two of Ruggiero's friends clashed in a dispute, sparked by a careless remark about sleeping with the other's sister. As swords were drawn and a violent confrontation ensued, it was the innocent musician who fell victim, his life extinguished amidst the chaos. The villa's inhabitants stood frozen in horror, witnessing the gruesome spectacle, while Ruggiero and his cronies merely chuckled at the misfortune of their fellow guest. This callous response drove Pampinea to the brink of madness, as she frantically sought to expel them from her domain.
However, Ruggiero and his companions took Pampinea's indignation in stride, mocking her feeble attempts at ejection. When Pampinea's loyal handmaiden Misia and Filomena rose to her defense, the men retaliated by lifting Filomena bodily and carrying her from the parlor, intending to "teach her a lesson." Horrified onlookers scrambled to intervene, but only Licisca's confession—that he had inadvertently betrayed his own kin by participating in this heinous act—served to halt the men's advance.
Ruggiero, infuriated by the revelation of deceit, issued a harsh command, ordering everyone's expulsion from the villa via the ignominious "whore door." The loss of two cherished friends left the group stunned and speechless, yet none dared to confront the wrath of Ruggiero and his companions. It was Panfilo's timely intervention that momentarily restored a semblance of calm, though the fragile peace hung precariously in the balance.
Just as tranquility seemed to have settled over the gathering, Sirisco, oblivious to the turmoil from the musician's demise to Filomena and Licisca's expulsion, storms back into the parlor, slinging a bag onto the table with a thud. From it, he extracts Leonardo's decomposing head, eliciting shrieks of horror from all present. Ruggiero, momentarily shattered by the ghastly sight, quickly recovers, recognizing his ascension to the villa's heirdom, and in a fit of triumph, promptly orders everyone's eviction. Through the kitchen, they are ushered out, where a surprising sight unfolds: Tinardo and Stratilia emerge from a hidden chamber, their erstwhile quarrel transformed into a fiery embrace, their night spent entwined in secrecy. Stratilia insists their union must remain undiscovered, while Tinardo revels in every stolen moment.
As the banished group spills out into the gardens, a sinister spectacle unfolds. A horde of prostitutes descends upon Ruggiero and his men, at least one of them afflicted with a sinister, plague-ridden cough. Amidst the revulsion and disgust directed at these women, Neifile, ever the lustful one, stealthily sneaks back inside the mansion, her desires undeterred by the chaos outside.
