May be becuase it is lready 4th part of the game but you might have some problems with understanding it. Or not if you happen to be a sci-fi devotee who can create a dozen of alien species in your mind in just a second. Anyway the Grand Xenozork has landed! His powers has ampiied since his sexual predominance of the Empress. Now the next wave of girls must be conquered with Xenozork's golden pheromones! Just keep attention to the stregth of pheromons - if the will be too strong the girls will crank out and sound the alarm. Get them horny again until they will be too humid to resist. As for the gameplay your purpose seem to be to combine the different colored pheromones in a way that will allow you to defeat and use all these huge-titted space amazons which you will meet on your way to greatness.
It is time for a short joke story again - just thrust begin button and have some fun without any gameplay. But be warned that this is an adult joke and it is involving strange looking alien at some point so who knows what you will see during this animation... The story embarks on one plain morning which stops being plain at the same second as big flying spaceship appears in the skies above the white palace. And this is clearly not a spaceship made by humans so looks like first contact with aliens is about to happen... probably that is why the ship is surrounded by tanks and militaries. But this alien guy who has arrived on this ship is not frightened of them so he walks out to deliver the message... let's just hope that people will understand him correctly despite the shape that his assets has.