I just love this, love everything about it.
And it touches my personal history. Let me see... singing Zeppelin tunes in a band in high school in 1969, check. Met Robert Plant at a party in the mid-70s, and had a pleasant chat about singing harmony, affirmative. Loved Heart from the very first listen, and watched them blow The Eagles off the stage somewhere in California in 1980, yea and verily.
Finally, one must never underestimate the power of a great big stealth choir.