I Am Number Four is a fast-paced YA novel about a boy named John Smith. John's secret? He's actually an alien, one of nine children chosen to rebuild the planet after it was destroyed by another, more violent alien race. The nine survivors can only be killed in order due to a spell; the novel opens with John receiving a third scar, indicating that Three has died and he is next. 
 The premise isn't bad; in fact, it's interesting. The pacing of the plot breaks the story for me. Everything moves so quickly and with so little explanation. The characters have no time to develop or show complexity because one event happens immediately after another. There's no time for them to breathe, let alone develop. The lack of development makes John seem incredibly childish and hard to relate to. The romantic lead, Sarah, is an ex-cheerleader who decided to be nice instead; because she never develops beyond this, she remains especially contrived and flat as a character. 
 I read this in college, so I can't say how younger readers might like it. Maybe this is a better fit for younger YA readers.