Gemma reveals Maureen's letters to Jax on part one of the season four finale, encouraging him to kill Clay and take his rightful place as President of SAMCRO. But Tara also has a scheme.
She actually gives Jax the weapon that will cause Clay's lungs to fill with blood - he's in the hospital, following last week's shooting by Opie, who Jax has dropped at a different hospital, after putting a bullet through his wrist - and also encourages him to make the kill... but then to return home, pick her and the boys home and leave Charming for good.
Elsewhere, Tig responded to Clay's shooting by going rogue. He tried to run down LeRoy - Jax, Clay and Unser agreed to make it look like a Niners hit - with his car, killing the leader's girlfriend in the process. Gotta figure that will have repercussions.