Seán Ceataigh (Máire's father) comes to see Séadna. Micil thinks the deal is done, but he doesn't hear the conversation. Séadna goes to see the priest. He finds out that Máire would be upset not to marry him, and tells the pries that things are much worse than he thought!
The priest can't figure out what's wrong with Séadna. The priest thinks he has it, and in telling Séadna, gives him the way out - "ar son an tSlánaitheora!"