Battle of Assassin (S01E12)

Lugh and Dia's father devise a scheme to fake Dia's death in order to smuggle her into the Tuatha Dé territory safely. However, their plan is interrupted by the unexpected arrival of Setanta MacNess. Aware that a direct battle with Setanta, the bearer of Gae Bolg, would be disastrous, Lugh launches a tungsten projectile into the sky, buying time until it destroys Setanta. With the threat eliminated, the Tuatha Dé family takes Dia in, pretending she is Lugh's younger sister, successfully completing their mission. Later, Lugh learns that the Hero, Lord Epona Rhiannon, has reached the Alvan Kingdom.