When Pluto transits square to you natal Pluto, it’s a period of general regeneration. It’s an uprooting of the past and serves to eliminate all those things that are disagreeable. You have to look within to see how much you have managed to change and overcome. If it has not been done, it is now that you will have to face immense changes indicated by the sign which transiting Pluto squares (this is your natal Pluto sign) and by the house through which it transits.