Previously on Sons of Anarchy...
If you're just tuning in now because you heard that Charlie Hunnam peels for his art every week, I'm sorry, you're just going to have to settle for Jimmy Smits. And you are probably wondering what's going on with all these clothed people. May I suggest reading this recap of the first two seasons, this recap of the third season, and the following paragraph? The rest of you, skip ahead.
Last season on Sons of Anarchy: The club members who had gone to jail at the end of season three were released to the custody of a musical montage. They quickly figured out that things had changed in their short absence: Tara had already had her baby by Jax Teller; the new sheriff, Roosevelt, had no truck with a town full of racist bikers; Opie had finally decided to make an honest woman of his porn-star girlfriend, and they had the most awesome biker wedding.
Oh, and Clay decided that since he and Gemma hadn't really been keeping up on their 401(k) contributions, he'd finance their retirement by dragging the entire club into running drugs for a Mexican cartel whose idea of employee incentivism was to randomly decapitate people. Jax, naturally, goes for it. He tells Tara that this is because he also wants to retire and leave the biker life behind, but he is afraid to do so unless he is clutching a security blanket woven with several hundred thousand dollar bills.
Of course Tara swallows this fiction, quite possibly because she's addled from the sleep deprivation that attends raising two children under age four while also maintaining a high-flying surgical career and attempting to keep Gemma penned within the boundaries of polite civilization.
(pause for rueful laughter here)
Gemma, however, is going to get the ball rolling on the events that will ultimately turn everyone inside out: she learns that Tara has damning letters that Maureen (John Teller's Emergency Backup Old Lady) sent to Jax, freaks out all over Clay, and he decides that since Tara knows Clay and Gemma killed John Teller, she's got to die. In the course of Clay's quest to kill Tara, he contracts for her killing, but the attempted abduction is botched, leaving Tara with a broken hand. Remember, this is a woman who was a surgeon.
Clay also kills Piney. Opie finds out, goes to kill Clay, misses the shot and Clay lies to everyone else and claims the One-Niners did it out of pique over the drug running. Naturally, this sends Tig out on a mission to avenge his father figure/BFF and Tig manages to kill the daughter of a prominent gangster, because if you want to make sure the wife or girlfriend of a gangster dies by accident, Tig's your guy.