Actually they tell a story about a knight who has lied half-dead in a rill (probably after a battle) and now tries to get up again (may be he even was dead and now ressurrects), to "drag himself back into man's world, thinking he came from there". He doesn't crawl into a tower, I would translate the stanza with the tower to "The clockwork of the grand time of man breaks teeth, scurf and darkness. The big one is set to cessation, the small one is set to storm. Tired even the bell rings, up in the church spire." The knight dies as an unknown dead and will "step down into the black mirror of the soul". (Excuse me for not keeping any sense of poetry.) Most of the lyrics describe the knight's hopelessness and physical pain.
So from what I can tell the lyrics tell a story about a guy that crawls into a tower and dies, not too sure cus the translation site sucked though. Does anyone here want to explain what the song is really about? Because it's a favorite of mine and I can't really decipher the lyrics.