An Eko-centric episode the "?" explores the aftermath of the tragic events that rocked the castaways in the previous one. As the main characters John, Locke, Sawyer, Kate and Hurley come to terms with the incident in the hatch, Locke and Eko set out to find out where Henry took off to. As it turns out Eko is on a mission of his own trying to figure out the symbol ? which Locke had drawn on his sketch. We see flashes of Eko's life in Sydney as a priest who comes in contact with his brother through a stranger. We also witness the tragedy that struck the hatch boil down to a room temperature as Michael continues to remain a mystery.

An excellent LOST episode with many interesting turns.