Now, many of us are preparing our eyes for a bit of rolling on Sunday night at 10, when Showtime airs the second season finale. OK, so the CIA is letting a former agent they know is unstable take the lead on a mission — and fall in love with the enemy — to protect the country. That former agent’s family no longer seems to care about her. Meanwhile, the CIA has also trusted Brody, a sleeper terrorist, a congressman who does no congressman-ing, never suspecting him in the murders of Bassel the tailor or the vice president. And on and on, as I’ve detailed in the Globe along the way. The gaps have been getting wider with each eventful episode, with the kinds of absurd plot holes that made “24” a live-action cartoon.