diff --git a/racket/syndicate/hierarchy.rkt b/racket/syndicate/hierarchy.rkt
index 9f7ff4e..c246f78 100644
--- a/racket/syndicate/hierarchy.rkt
+++ b/racket/syndicate/hierarchy.rkt
@@ -11,6 +11,8 @@
          level-anchor
          level-anchor->meta-level)
 
+(require "store.rkt")
+
 ;; An event destined for a particular node in the actor hierarchy.
 ;; Used to inject events from the outside world.
 (struct targeted-event (relative-path event) #:prefab)
@@ -22,10 +24,10 @@
       (targeted-event relative-path event)
       event))
 
-;; Parameterof (Listof Any)
+;; Storeof (Listof Any)
 ;; Path to the active leaf in the process tree. The car end is the
 ;; leaf; the cdr end, the root.
-(define current-actor-path-rev (make-parameter '()))
+(define current-actor-path-rev (make-store #:default-box (box '())))
 
 ;; Retrieves current-actor-path-rev, but reversed, for use with
 ;; target-event.
@@ -34,7 +36,7 @@
 ;; Any (-> Any) -> Any
 ;; Pushes pid on current-actor-path for the duration of the call to thunk.
 (define (call/extended-actor-path pid thunk)
-  (parameterize ((current-actor-path-rev (cons pid (current-actor-path-rev))))
+  (with-store ((current-actor-path-rev (cons pid (current-actor-path-rev))))
     (thunk)))
 
 ;; Retrieves an abstract value to be used with level-anchor->meta-level to compute a
diff --git a/racket/syndicate/store.rkt b/racket/syndicate/store.rkt
index 777a403..18f9c6d 100644
--- a/racket/syndicate/store.rkt
+++ b/racket/syndicate/store.rkt
@@ -8,17 +8,18 @@
          store-ref
          store-set!)
 
-(struct store (mark-key)
+(struct store (mark-key default-box)
   #:property prop:procedure
   (case-lambda
     [(s) (store-ref s)]
     [(s v) (store-set! s v)]))
 
-(define (make-store)
-  (store (make-continuation-mark-key (gensym 'store))))
+(define (make-store #:default-box [default-box #f])
+  (store (make-continuation-mark-key (gensym 'store)) default-box))
 
 (define (store-box s)
   (or (continuation-mark-set-first #f (store-mark-key s))
+      (store-default-box s)
       (error 'store-box
              "Attempt to access store that is not currently in scope")))
 
diff --git a/racket/syndicate/threaded.rkt b/racket/syndicate/threaded.rkt
index b133f68..e7b1021 100644
--- a/racket/syndicate/threaded.rkt
+++ b/racket/syndicate/threaded.rkt
@@ -10,6 +10,7 @@
 (require (except-in syndicate dataspace))
 (require (only-in syndicate/actor actor dataspace schedule-action!))
 (require syndicate/hierarchy)
+(require syndicate/store)
 
 (struct proxy-state (thd) #:prefab)
 (struct thread-quit (exn actions) #:prefab)
@@ -55,7 +56,7 @@
 
   (define (deliver-event e proc)
     (process-transition proc
-                        (parameterize ((current-actor-path-rev actor-path-rev))
+                        (with-store ((current-actor-path-rev actor-path-rev))
                           (with-handlers [((lambda (exn) #t) (lambda (exn) (<quit> exn '())))]
                             ((process-behavior proc) e (process-state proc))))))