Eternal Lies is a 2013 adventure campaign for Trail of Cthulhu by Will Hindmarch and Jeff Tidball, with additional writers, published by Pelgrane Press. A massive campaign in the tradition of Masks of Nyarlathotep, it sets the investigators against a worldwide cult and the alien forces behind it in an escalating quest to save humanity.
The print edition was also released in a special pre-release bundle with a soundtrack album by James Semple and a PDF. It won the 2014 Gold ENnie for Best Adventure and the Silver ENnie for Best Production Values. Justin Alexander of The Alexandrian wrote that, despite the very high esteem in which he holds Masks of Nyarlathotep, he considers Eternal Lies even better.