The 
(defmacro cl:multiple-value-bind (symbols expr &rest body)
  (and (or (not (consp symbols))
           (eq 'quote (first symbols))
           (dolist (symbol symbols)
             (or (symbolp symbol) (return t))))
       (error "not a list of symbols" symbols))
  (setq cl:*multiple-values* nil)
  (let* ((result (eval expr))
         (values (if cl:*multiple-values*
                     *rslt*
                     (list result)))
         (number-of-symbols (length symbols))
         (number-of-values  (length values))
         (bindings nil))
    (dotimes (index number-of-symbols)
      (push (if (< index number-of-values)
                (list (nth index symbols)
                      (list 'quote (nth index values)))
                (nth index symbols))
            bindings))
    (setq bindings (reverse bindings))
    `(let ,bindings ,@body)))
The 'values' expression is evaluated, and each of the symbols is bound to
the respective value returned by the evaluation. 
The 
> (macroexpand-1 '(cl:multiple-value-bind (a b c)
                      (cl:values 1 2 3)
                    (list a b c)))
(LET ((A (QUOTE 1))
      (B (QUOTE 2))
      (C (QUOTE 3)))
  (LIST A B C))
The quotes are necessary to prevent 'unbound variable' and 'unbound function' errors with symbols and lists.
Examples:
1. The 
(defun multiple-value-function ()
  (cl:values 1 2 3))  ; multiple return values
> (cl:multiple-value-bind (a b c)
      (multiple-value-function)
    (list a b c))
(1 2 3)
2. If there are no values returned in the Nyquist
*rslt* variable, the normal
function return value is bound to the first symbol and all remaining symbols
are bound 
(defun normal-lisp-function ()
  (+ 1 1))  ; normal return value
> (cl:multiple-value-bind (a b c)
      (normal-lisp-function)
    (list a b c))
(2 NIL NIL)
3. If there are less values than symbols, the extra symbols are
bound 
(defun not-enough-values-function ()
  (cl:values 1 2))  ; multiple return values
> (cl:multiple-value-bind (a b c)
      (not-enough-values-function)
    (list a b c))
(1 2 NIL)
4. If there are more values than symbols, the extra values are ignored:
(defun too-many-values-function ()
  (cl:values 1 2 3 4 5))  ; multiple return values
> (cl:multiple-value-bind (a b c)
      (too-many-values-function)
    (list a b c))
(1 2 3)