2 Samuel ch.3 - Reconciliation. And an Assassination

Avner argues with the King, Ish-Boshet, and as he realizes that the northern faction led by Sauls' son, is weakening, he decides to capitalize on the moment and create a coalition with King David. However Yoav, David's general, has a vendetta with Avner (Avner had killed Yoav's brother) and he murders Avner. Now the peace deal is severely jeopardized. Will David manage to salvage the peace and reunite the kingdom under his rule?