Agape is Zhang Liyin's third overall single, released on August 2, 2014 in China and August 6 in Korea. The song is dedicated to the victims of the 2008 Sichuan earthquake. Co-written by Zhang Liyin and Taiwanese lyricist , the song is about a mother who allows her child to live at the expense of her own life. The single's B-side track "Back Then" is a cover of the title song from Taiwanese film You Are the Apple of My Eye.

On May 26, 2014, S.M announced that label mate f(x) Victoria will be the main lead for Zhang's music video. Actor Song Jae-rim and EXO member Tao were later confirmed as added to the cast through various Korean news sites on June 18. The music video teaser was released July 25, and the full music video was released August 5. Both were released on the SM Town official YouTube and YinYueTai channel. The song was released August 2, 2014 on Baidu Music for China, and released in South Korea through online music stores MelOn and Genie on August 6, 2014.

The music video is a tribute to the victims of the 2008 Sichuan earthquake. The plot is based off a true story of a selfless mother who protected her child throughout the 7.9 magnitude earthquake.

When the mother was discovered by the rescuers, she had already died from the house that collapsed. However, the rescuer noticed her unusual posture, kneeling on the ground with both of her arms supporting her upper body. When people cleared away the rubble around her, they found her 3 to 4-month-old baby, wrapped in a blanket, sleeping soundly under her, still alive. After that, the rescuing doctor found a mobile phone inside the baby's blanket and on the screen was a message that said: "My beloved baby, if you can survive, please remember that I love you."

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