After sending Philia and Hero off, Pseudolus first tries to tell Hysterium she is his daughter. They are about to go, but Philia reminds them all she is duty-bound to honor the contract with Miles Gloriosus. Pseudolus, realizing he will lose his chance for freedom if Philia does not run away with Hero, puts Philia in Senex's house to wait for the captain, whose arrival Pseudolus will announce with three knocks on the door. After calling out for Pseudolus, Senex goes to the door of his house and knocks three times. She throws herself at him just as Pseudolus returns with a vial of mare's sweat.
Philia exits back into the house.
When Senex asks Pseudolus who she is, he tells him that she is the new maid. Before Senex can enter his house to meet Philia, Pseudolus sprinkles some mare's sweat on Senex and convinces the old man he needs a bath after his long trip. Senex goes off to the empty house of Erronious to take his bath and wait for Philia. A very nervous Hysterium returns in time to see Senex enter Erronius's house. With Hysterium frantically gesturing behind Erronious, Pseudolus guesses the nature of Erronius's long trip abroad and tells him he can find his long-lost children.