For such a relatively new band, Monofog has a complicated history. The Fort Collins outfit started in 2001 and quickly kicked up a buzz with its atmospheric, cerebrally aggressive indie rock. In 2003, though, drummer Lucas Rouge moved out of state; three of the remaining members -- singer Hayley Helmericks, guitarist Doug Spencer and bassist David Yob -- regrouped under the name Ready Machete and began exploring the territory of synth-stabbed post-punk. But upon Rouge's return late last year, Monofog reconvened (with guitarist Blake Brown replacing founding member Justin Loendorf) and released a stunning self-titled EP that was actually recorded before the hiatus. Binding noise and harnessing dissonance in the tradition of Unwound and Blonde Redhead, the record twists melody into intense and entirely contorted configurations, all laced with Helmericks's seething, impassioned vocals. Come to the Boulder Theater on Saturday, March 12, where Monofog will be appearing with Matson Jones and Mannequin Makeout, and help welcome back one of Colorado's most vital and promising young bands.