Cesare Angelotti, escaped political prisoner
Mario Cavaradossi, a painter
Floria Tosca, a singer, Mario’s girlfriend
Baron Scarpia, chief of the secret police
Spoletta, a spy
Rome, June 1800. Napoleon, an army general and ruler of France, is invading Rome. Mario, Tosca, and Cesare want Napoleon to win. The Baron Scarpia is fighting against Napoleon.
Cesare Angelotti, loyal to Napoleon, escapes from jail and rushes into a church to hide. Mario Cavaradossi is there, working on a painting. Mario hides his friend Cesare in the back of the church. Mario’s girlfriend Tosca comes in, and wonders if the sneaking around means Mario has a new girlfriend. Mario tells her he loves only her. As she leaves, they hear the alarm go up: the secret police are hunting for Cesare. Mario and Cesare run away to Mario’s house.
Baron Scarpia, chief of the secret police, arrives at the church looking for Cesare. Tosca comes back looking for Mario. The Baron thinks Tosca knows something, and he tells her Mario is in love with Cesare’s sister, to make her jealous. Tosca is angry and runs off to find Mario. The Baron’s spy Spoleta follows her.
Spoletta brings Mario to the Baron’s palace, and sends him to jail in the castle. He sends for Tosca and tells her he will hurt Mario if she doesn’t tell him where Cesare is hiding. She tells him, and Cesare is killed.
Now the Baron tells Tosca that he will kill Mario unless she agrees to be his girlfriend. Tosca says she will, if the Baron will let Mario go. The Baron promises to only pretend to execute Mario, for show, then let him go. She makes him write down his promise. As soon as he is done writing, Tosca kills him with a knife she hid in her clothes! She takes the promise he wrote.
Tosca sneaks into Mario’s castle jail cell. She tells him about the pretend execution, shows him the letter, and says that soon they will both be free together. When soldiers come, she hides, sure that they will only pretend to kill him. But the Baron betrayed Tosca; when they fire their guns, the bullets are real and Mario is dead! Spoletta rushes in to arrest her for murder. She cries out and tries to escape, leaping from the castle wall. Tosca dies.