By Julie Moult for MailOnline. The magnetic chemistry between the two has been simmering for all to see since the pair first crossed paths. And just as it seems Homeland's Carrie Mathison and assassin-with-a-heart Peter Quinn may finally get it on as they share a passionate kiss, their path to romance is torpedoed once again. In the Showtime season four finale on Sunday, fans also learn dastardly Dar Adal has been making deals with US public enemy number one, the Taliban leader Haissam Haqqani. The kiss: The simmering sexual tension between Peter Quinn and Carrie Mathison comes to a head in the season finale. Back on American soil, in Sunday night's season closer Long Time Coming, he reveals to his old colleague and sometime friend Saul Berenson that he had been able to strike a deal with Haqqani. In return for taking his name off the US kill list, Haqqani agreed to no longer harbor terrorists in Afghanistan, he explained.