Gibbs and the three musketeers catch a snail during an apparent burglary; the next morning they learn about a fire in the galley aboard a Naval vessel in the Atlantic Ocean; then Vance tells Gibbs that Jackson, Gibbs's father, has had a stroke and died; Gibbs goes to Stillwater, Pennsylvania, his hometown. The gang learn that the fire resulted from arson by an incendiary device. Abby finds a connection between the fire and the supposed burglary; Tony learns more and hears a familiar name, then he disobeys an order by calling Gibbs; both Tony and McGee pursue Abby's lead; Gibbs returns to work. Ellie finds a key player, then she and McGee learn much from her. At home Gibbs receives a visitor and deals with him, then Gibbs meets with Rivera. Abby gives a big warning. Inside Jackson's shop Gibbs receives another visitor and deals with him too, then he goes to his father's funeral and burial, where the whole gang, including Vance, along with L.J. Moore, join him.