What is ego? I prefer the following definition by Cambridge Dictionaries:
Your idea or opinion of yourself, especially your feeling of your own importance and ability
Actually, wait. There’s a psychological definition as well:
In psychoanalysis, the part of a person’s mind that tries to match the hidden desires (= wishes) of the id (= part of the unconscious mind) with the demands of the real world
Mars is to assert yourself. Why would you assert yourself? To get what you want, desire. To satisfy your ego. When Pluto contacting Mars, the Hades of Hell has burned down your door, whether you want it or not. Hades eh. Think the king of the underworld. Think power. Raw sheer power.
So, with Pluto-Mars transits, there could be sheer raw power available to assert yourself to satisfy your ego, when channelled properly which can be tougher with hard aspects. You have huge and deep reservoir of strength at your disposal, especially when it comes to achieving your ambitions which would have an effect on your home and family life. Be weary of overwork and burning out though. Your human body can only take on so much power.
Returning to the imagery of Hades, think ruthless. Think of actions without regard for other people – whether it’s well-intentioned people with well wishes or enemies. You may do anything to get what you want. Certainly, if you are blocked in your pursuits, you can fight (Mars) and most probably win. But if you can also make a friend after winning, why not eh?
Depending on how you react with the Plutonian energies, it is possible that you project those energies onto other people, people in your life. If that’s the case, you may find that you have to fight against them. This can feel overwhelming but really, it offers you the opportunity to get in touch with your power. Be cautious of those who use underhand (which goes with the underground theme of Hades) methods and tactics to get their way.
Finally, Pluto uncovers something within you. In this case, it’s Mars. Check the natal location of Mars along with the houses ruled/co-ruled to see what hidden treasures are waiting to be uncovered by you.