"This place is a ritual center... part of a great calendar!"―Indiana Jones[src]
The mound near New Grange housed an underground archaeological site. In ancient times, it was used as a Celtic center for equinox-based rituals, and contained spiral carvings. It was located not far from New Grange, Ireland. One of the spiral carvings on the floor was the Stone of Fal.
In March 1945, Indiana Jones led an excavation of the site, assisted by Brendan O'Neal and several other men. Late one afternoon, they discovered some additional spiral carvings in the rock wall, which Jones estimated to be at least 500 years older than the Egyptian pyramids. O'Neal pocketed a small stone, cut with a spiral design. Leaving for the night, O'Neal met a mysterious blond woman who had a letter and a meal for Dr. Jones. Warning Jones that she might be of the fairy folk, O'Neal departed. Jones took the letter and returned down into the mound. The woman reflected a light into the barrow, which bounced around and stunned Jones. Jones hit his head, and had a vision about the Spear of Longinus and was commanded to find it before it could be used by Adolf Hitler. While unconscious, Jones was found outside the mound and brought back to Connely's Inn, where he was staying. Later that night, Jones was forced to flee from Ireland, and escaped with O'Neal to England.
A night or two later on March 21, O'Neal and Henry Jones, Sr. arrived at the mound, with half of the spear tip and a sprig of the Holy Thorn. While assembling the pieces onto a yew shaft to recreate the spear, the two realized that the Spear of Lugh, from Celtic legend, was likely the same as the Spear of Longinus. When Indiana Jones and Rebecca Stein arrived, they revealed that they had stolen the last half of the spear tip from the Nazi youth Seigfried, but when they unwrapped the package, it turned out to be a fake. Seig's father, Dieterhoffmann arrived, along with his men. The genuine spear tip half flew from Dieterhoffmann's pocket to attach itself on the spear assembled by O'Neal, which flew around the room, killing Kurt.
The mound started collapsing, causing everyone to seek safety. O'Neal stepped onto a spiral stone, which began shrieking as the Stone of Fal, with O'Neal revealed as true king of Ireland. Commanding the Spear to come to him, O'Neal was hit by the spear, but Henry Jones pulled it out, and the morning light of the equinox shone into the mound, illuminating the spear and the spiral. Indiana Jones recognized the purpose of this mound as a ritual center. Professor Jones, Dieterhoffmann, and Seigfried all witnessed that blood flowed from the tip of the spear - a holy marvel. The mound started to collapse, and Henry dropped the spear. With Dieterhoffmann bleeding to death from being unworthy to see the spear, and Seigfried occupied in rapturous prayer, Otto Nehrkorn stole the spear tip and escaped. As the mound caved in, Indiana Jones pulled Seigfried to safety, but the youth expired outside in the morning light. The stones holding up the mound crumbled inward, burying the site, and grass sprouted over the site, which O'Neal remarked as a sign from the fairy folk not to dig there anymore. Expecting that the Irish government would say something similar, Jones packed up for adventures elsewhere.