Reborn vs Evil Hitmen is the 176.1st chapter of Akira Amano's Katekyo Hitman Reborn! and is assumed to take place before the Future Arc, therefore this chapter takes place in Namimori present.
Note: This one-shot was published on the magazine Jump Heroes on June 30, 2005 as a special chapter. Then it was recompiled in the databook Katekyo Hitman Reborn! Vongola 77.