Initially the single was only released on the Internet and radio, with the release date to May 30, 2007, together with the revealing of the identity of the new vocalist (Anette Olzon), but due to a leak on May 23, the vocalist identity was revealed on May 24, and the song was released on the 25th. Officially, "Eva" started to play on Finnish radio stations YleX and Radio Rock at 7 AM, May 25, and was available as a download the same day.
All European income from this release were donated to charity (Child Charity Foundation), and the income from Finnish Internet sales were donated to two children's homes in Finland.
Eva's cover was announced on the official website on May 17. It features a young girl dressed in 19th century Finnish clothing with a teddy bear in front of a house by night.
"Eva" was the first Nightwish single featuring Anette Olzon (pictured).
The song is about a young girl of pure innocence, called Eva, who has been treated wrongly in her life, and her escape from her home as she runs away alone for a better future, dreaming of what will come.
According to a diary entry posted to the official Nightwish website by the new vocalist on May 13, 2007, "Eva" is a soft, sad and emotional song. A sample of the track has been posted on the internet some days before the release with the following lyrics: "(...)She walks alone but not without her name. Eva flies away, dreams the world far away. In this cruel children's game, there's no friend to call her name (...)",