The installation of an oratory in the ground floors of a block of flats led to the protesting of the neighbors who complaint about the place not having the conditions to accommodate a place of worship. The Muslim community had been given a provisional license by the Town Council so that they could celebrate Ramadan and then move somewhere else. But the neighbors complaint because they had been deceived by the Town Council: they had been protesting for months against the opening of this oratory. Once the conflict ended with the relocation of the oratory in a waste ground outside Santa Coloma, "No mosque!" tries to be a documentary about dialogue and reflection, about the facts, reasons and consequences of a case which is neither the first nor the last of this nature and which is more and more common in the European society, recipient of a great number of immigrants.