A book over 600 years old.

240 pages of handwritten symbols, strange botanical illustrations, and astronomical diagrams.

No one knows what language it's written in.

No one knows who wrote it.

No one knows what it means.

Linguists have failed. Cryptographers have failed. Historians have failed. Even artificial intelligence has failed.

The Voynich Manuscript sits in Yale University's library right now — fully scanned, available for anyone to see.

And still. No one can read it.

This is WREN SIGNAL. Every episode, we follow one mystery. One signal that was never fully explained.

Some signals are never meant to be clear.