Mastermind is the third mini-album by South Korean boy band Beast,[1] and was released by Cube Entertainment on September 30, 2010.

[3] On September 24 at 10 AM KST, a teaser video for the lead single "Soom" was released on Beast's official homepage and other various online portal sites.

[3] In the teaser, member Yong Jun Hyung was seen lying on the ground where Son Naeun, dressed in red, put on an oxygen mask for him and gains conscience.

[3] On September 25 and 26, teaser audio clips for "Soom" were revealed on KBS's COOL FM Narsha's Raise the Volume.

A military-look concept photo for Mastermind was revealed on September 27, showing off Beast's manly side along with a chic modern feel.