diff --git a/org-clock-agg.el b/org-clock-agg.el
index 7eb1f91..448b01d 100644
--- a/org-clock-agg.el
+++ b/org-clock-agg.el
@@ -29,6 +29,67 @@
 
 ;;; Code:
 (require 'compat)
+(require 'org)
+(require 'org-ql)
+
+;; Reset org-ql cache
+(setq org-ql-cache (make-hash-table :weakness 'key))
+
+(defun org-clock-agg--parse-clocks (headline)
+  (let ((contents (buffer-substring-no-properties
+                   (org-element-property :contents-begin headline)
+                   (org-element-property :contents-end headline))))
+    (with-temp-buffer
+      (insert contents)
+      (let (res)
+        (org-element-map (org-element-parse-buffer) 'clock
+          (lambda (clock)
+            (let ((start )
+                  (end (time-convert
+                        (org-timestamp-to-time (org-element-property :value clock) t)
+                        'integer))))
+            (push
+             `((:start . ,(time-convert
+                           (org-timestamp-to-time (org-element-property :value clock))
+                           'integer))
+               (:end . ,(time-convert
+                         (org-timestamp-to-time (org-element-property :value clock) t)
+                         'integer)))
+             res))
+          nil nil 'headline)
+        res))))
+
+(defun org-clock-agg--parse-headline ()
+  (let* ((headline (org-element-headline-parser))
+         (tags-val (org-ql--tags-at (point)))
+         (tags (seq-filter
+                #'stringp ;; to filter out `org-ql-nil'
+                (append (unless (eq (car tags-val) 'org-ql-nil)
+                          (car tags-val))
+                        (unless (eq (cdr tags-val) 'org-ql-nil)
+                          (cdr tags-val)))))
+         (file (buffer-file-name))
+         (outline-path (mapcar
+                        #'substring-no-properties
+                        (org-ql--outline-path)))
+         (category (org-get-category)))
+    `((:headline . ,headline)
+      (:tags . ,tags)
+      (:file . ,file)
+      (:outline-path . ,outline-path)
+      (:category . ,category)
+      (:clocks . ,(org-clock-agg--parse-clocks headline)))))
+
+(defun org-clock-agg--query (from to files)
+  (org-ql-query
+    :select #'org-clock-agg--parse-headline
+    :from files
+    :where `(clocked :from ,from :to ,to)))
+
+
+(defun org-clock-agg ()
+  (interactive)
+  ())
 
 (provide 'org-clock-agg)
 ;;; org-clock-agg.el ends here