diff --git a/classes/ComicPressStoryline.inc b/classes/ComicPressStoryline.inc
index 7b6bf87..77d46a5 100644
--- a/classes/ComicPressStoryline.inc
+++ b/classes/ComicPressStoryline.inc
@@ -142,6 +142,7 @@ class ComicPressStoryline {
 
   function _get_field($field, $id) {
     if (isset($this->_structure)) {
+    	$id = $this->_ensure_numeric_category($id);
       if (isset($this->_structure[$id])) {
         if (isset($this->_structure[$id][$field])) {
           return $this->_structure[$id][$field];
@@ -157,8 +158,9 @@ class ComicPressStoryline {
   function next($id)     { return $this->_get_field('next', $id); }
   // @codeCoverageIgnoreEnd
 
-  function valid($id)    {
-    if (isset($this->_structure[$id])) {
+  function valid($id) {
+    $id = $this->_ensure_numeric_category($id);
+  	if (isset($this->_structure[$id])) {
       return array_keys($this->_structure[$id]);
     }
     return false;
diff --git a/functions.inc b/functions.inc
index 6d4c5fc..2634d25 100644
--- a/functions.inc
+++ b/functions.inc
@@ -172,4 +172,33 @@ function SL() {
 	$storyline = new ComicPressStoryline();
 	$storyline->read_from_options();
 	return $storyline->_structure;
+}
+
+function SC($which, $relative_to = null) {
+	global $post;
+
+	$storyline = new ComicPressStoryline();
+	$storyline->read_from_options();
+
+	if (is_null($relative_to)) {
+		if (is_object($post)) {
+			if (isset($post->ID)) {
+				$categories = wp_get_post_categories($post->ID);
+				if (is_array($categories)) {
+					$relative_to = reset($categories);
+				}
+			}
+		}
+	}
+
+	if (!is_null($relative_to)) {
+		if ($result = $storyline->_get_field($which, $relative_to)) {
+			$category = get_category($result);
+			if (!empty($category)) {
+				return $category;
+			}
+		}
+	}
+
+	return false;
 }
\ No newline at end of file
diff --git a/test/FunctionsTest.php b/test/FunctionsTest.php
index 894763b..1cb5e72 100644
--- a/test/FunctionsTest.php
+++ b/test/FunctionsTest.php
@@ -188,4 +188,37 @@ class FunctionsTest extends PHPUnit_Framework_TestCase {
 
 		$this->assertEquals($s->_structure, SL());
 	}
+
+	function providerTestSC() {
+		return array(
+			array('next', 1, 2),
+			array('next', null, 3),
+			array('next', 4, false),
+			array('test', 4, false),
+		);
+	}
+
+	/**
+	 * @dataProvider providerTestSC
+	 */
+	function testSC($which, $relative_to, $expected_result) {
+		global $post;
+
+		$post = (object)array('ID' => 1);
+		wp_set_post_categories(1, array(2));
+
+		$s = new ComicPressStoryline();
+		$s->set_flattened_storyline('0/1,0/2,0/2/3,0/2/4');
+
+		for ($i = 1; $i <= 4; ++$i) {
+			add_category($i, (object)array('slug' => 'test-' . $i));
+		}
+
+		$result = SC($which, $relative_to);
+		if ($expected_result === false) {
+			$this->assertTrue(false === $result);
+		} else {
+			$this->assertEquals($expected_result, $result->term_id);
+		}
+	}
 }