Smallville - Season 4 Episode 15 -

The Kryoptonian metallic disc is returned to Clark following the death of Virgil Swann. Placing the disc in the cave reveals a message from the spirit of Jor-El instructing Clark to find the three Kryptonian knowledge crystals and unite them before others find them and use them to self-interest. The message goes on to tell Clark that allowing a human to assemble the crystals could lead to the destruction of Earth. The first stone, retrieved by Lex in Egypt in the season opener, is in Clark's possession in the cave. The second is apparently in possession of the late ...