Board Thread:Speculation House/@comment-50.159.23.176-20140915201458

So I've been thinking,

In episode 6 (of volume two) Yang told Blake that Summer Rose left on a mission one day but never came back, which may mean they don't know what happened to her.

But in the Red trailer Ruby was standing at a grave stone that belonged to Summer, so at first I thought,  maybe she's still alive? But if so, why was there a grave for her?

(And now I'm confusing myself because basically, I want to know that if No one knows where Summer is and if she died, why would there be a grave? was it just in her memorial? (if so am I jsut over thinking it?) 