SISTAR has dropped another image with a "riddle" on it for their summer comeback - except this time, it's pretty illegible.

However, you can distinctly make out the words, "Only you have to disappear."  Gives off a psychotic, murder-y thriller vibe, doesn't it?  Maybe the girls will return with a more darkly sexy concept like "Alone" rather than their usual bright and cheery one for the summer.

Stay tuned for their fourth mini-album!  

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