--- a/src/rps_nickserv.erl	Sat Mar 08 15:37:47 2014 +0900
+++ b/src/rps_nickserv.erl	Sat Mar 08 18:39:51 2014 +0900
@@ -14,7 +14,11 @@
     {reply, ok, dict:store(Who, Nickname, Nicknames)};
 
 handle_call({whois, Who}, _From, Nicknames) ->
-    {reply, dict:fetch(Who, Nicknames), Nicknames}.
+    N = case dict:find(Who, Nicknames) of
+            {ok, Nickname} -> Nickname;
+            error -> Who
+        end,
+    {reply, N, Nicknames}.
 
 handle_cast(_Msg, State) -> {noreply, State}.