The Vigil of Easter is at 7:30 PM, followed by the Mass of the Resurrection.
On Holy Saturday the Church waits at the Lord’s tomb, meditating on his suffering and death. The altar is left bare, and the sacrifice of the Mass is not celebrated. Only after the solemn vigil during the night, held in anticipation of the resurrection, does the Easter celebration begin, with a spirit of joy that overflows into the following period of fifty days.
More at Wikipedia.
Image: A tomb in Jeruselem.