They say that behind every great man, is a great woman. Well the same goes for Doctor Isaac Kleiner, if you substitute "woman" for "alien parasite". But species doesn't matter. True love is all that matters to the good doctor. But when that love is violently taken from him, he resolves to exact revenge. Science Strikes Back has been called by some "a stylish and fast paced jaunt through Half-Life 2" and while that may be true, it will first and foremost, never be anything less than a true tale of revenge and lost love.