The title of The Penguin Episode 4 is "Cent'Anni", an Italian term that roughly means "100 years". It is generally used as a toast during times of celebration, and is supposed to serve as a wish for each participant to live long and reach the age of 100. Sofia Falcone (Cristin Milioti) uses it when addressing her family. However, her subsequent actions undermine that meaning and cause multiple deaths. Here is the explanation of the ending of The Penguin Episode 4.

The Penguin Episode 4 picks up where Episode 3 left off, focusing on Sofia as guns go off around her and she comes to terms with the enormity of Oz's (Colin Farrell) betrayal. Just before she passes out from her injuries, she manages to call Julian Rush (Theo Rossi). A flashback segment then unfolds, detailing how Sofia ended up in Arkham. In the previous episode, Sofia hinted that she wasn't the Hangman, and now that turns out to be true. The Penguin changes the Hangman's story. The series reveals that Carmine was the serial killer who murdered his wife and several other women. He framed Sofia for most of the recent murders after she spoke to reporter Summer Gleeson. While in Arkham, Sofia experienced horror, met Julian, and had her first experience with Bliss. She also committed her first murder there. Magpie (Margaret Pye) is a fictional character who has appeared sporadically in DC Comics. In The Penguin she lived in the cell next to Sofia, who killed Magpie because she feared she was spying for her father.

At this point, Sofia arrives unannounced at her family's dinner party and declares that she will start a new life the next day, leading the rest of the Falcones to believe that she will leave for Italy as planned. However, most of them, including Luca, do not wake up the next day, as Sofia has used some form of poison gas to kill them.

The flashback reveals that Carmine told Sofia that she was his intended successor. However, he got rid of her the moment she became a threat to him, and the rest of the family stood by him to betray her. The only person who stood by her through all of this was Alberto. His death and the desire for revenge on Oz serve as the primary motives for Sofia to kill Luca and other members of her family. Furthermore, this gave her control over the family business, which led her into the criminal underworld of Gotham City.