Episode 23 of "Lost"
s01e23 Exodus (1/3)

The French woman -- Danielle Rousseau (guest-star Mira Furlan)--- shocks the survivors by showing up to the camp with a dire warning about "the others" who are on the island. Meanwhile, Michael and Jin ready the raft for sailing. Danielle takes Jack, Locke, Kate, Hurley, and Arzt on a trek to the Black Rock. However, once they reach the "Dark Territory", Arzt (who had previously gone back to camp) came running with the real Beast hot on his heels. Fortunately, Locke's calm demeanor seemed to ease the "security system," as Danielle calls it, and it headed in the other direction. They eventually reached the Black Rock, which turns out to be a wooden ship. Also, black smoke was an ominous sign as the raft set sail after an accidental dely from Sawyer. Jin and Sun make up, and Walt decides to give the dog Vincent to Shannon since there was not room on the boat. The remaining 40 survivors plan to hide in the Hatch in anticipation of "the others."