There is an envelope, somewhere in England, bearing the handwriting of a Finnish musician. Inside is a proposal that, told in the abstract, sounds like the joke of a drunk poet: a symphonic metal band asks one of the planet's best-known evolutionary biologists to lend his voice to a twenty-four-minute song about the origin of life.

To understand how two worlds this far apart – the guitar and the ribosome, the double bass drum and the DNA – ended up in the same track, you have to start from a biographical detail almost nobody knows. Tuomas Holopainen, the man who has always written Nightwish's music, studied biology before becoming a full-time musician.