Based on the erotic game by ZION.

An elderly man who felt lonely and tired working all day after the mutation in Tokyo. Suddenly he was approached by 2 Gyaru prostitute who invited him to have sex openly to release the old man's loneliness. 2 prostitute have their own way, the first prostitute had sex with a condom for 30,000 yen and the second prostitute should not kiss, but only to have sex for 15,000 yen.

(Source: Translated and Edited from Nekopoi)