There is a scene in the film where V has taken Evey, a girl whom he had saved from rape from corrupt policemen into his home " The Shadow Gallery" in order to protect her from Norse- Fire due to her parents being once outspoken activist against the government. They were killed when she was very young and consequently put her into an orphanage. In the film, there is an arc where Evy gets taken hostage by " Norse-fire". She is then subjugated to torture regarding information on V. Eventually, she become non- fearful of death and fear lost it's grip on her. Evey was eventually let go by her captors. To Evey's shock, it was V all along who did those things to her.
In V's home " The Rouge Gallery"
V carries her away into the rain to soothe her anger. She then truly becomes free from the fears and horrors put forth by the ruling fascist government, the rain metaphorically washing them all away. This was the moment when Evey was convinced she must strike back and get back the liberties of her once great nation for her and for everyone.
V and his famous "Guy Fawkes mask" serves as a symbol for everyone in the world to unite together and voice out their ideas and protests. Strength in numbers. The power has always been with the people and not institutions or the government. Through the comic and movie, Guy Fawkes masks are used to unite various voices together as one. Instances in real life where the masks have been used are seen in anti-government protestors in Thailand and the 2011 Wisconsin protests to recall elections of state senators.