Well just because it's cliche doesn't mean it won't work! The details are really what matter. Who is "the guy?" What is his past, his personality, his goals? Who is this fallen angel? What is her relationship to the guy, or the evil man? Who is the evil man? Why is he evil, what does he really want? Who else important exists in this world?

Going beyond the characters, what is this portal? Where did it come from, how does it work, why does it exist? This crystal, what makes it so powerful? Who made it, or what? How does one tap into it's power? Why does the angel need it go get back to heaven?

Obviously if all you can come up with is "It just is" the story is gonna be dull as crap. If you can come up with original answers to these and other, similar questions you can take a boring premise and turn it into a creative story people want to read.