Why does "let" not evaluate, but just gives me #<promise>

Question

Something simple as this:

Welcome to DrScheme, version 4.2.3 [3m].
Language: Lazy Scheme; memory limit: 128 megabytes.

> (let ((x 2) (y 10))
   (+ x y))

#<promise>

> 

I press enter for the let expression, and it gives me the #<promise>. What am I doing wrong?