Hakunin dreams

Hakunin dreams are a series of four cutscenes appearing in Fallout 2, urging the Chosen One to find the G.E.C.K.

Arroyo's shaman, Hakunin, appears in the Chosen One's dreams asking them to hurry in saving the village. The dream sequences occur on October 23, 2241, January 21, 2242, April 21, 2242, and finally, on July 20, 2242. If Vault 13 has been entered, the fourth and final dream sequence immediately triggers after leaving Vault 13, skipping any previous left dreams. Arroyo will then be destroyed, with only Hakunin remaining behind to tell the Chosen One of the fate that has befallen their tribesmen, and will point the Chosen One toward Navarro.

July 20, 2242
or after leaving Vault 13 for the first time (after receiving the Experience Points for finding it)