Trouble returning HTML code in a function

I am trying to get a return on this function in functions.php:

function story_cat_slider () {
ob_start();

$contenth = “”;

$contenth .= ‘<div id=”storyslider”>

‘;

query_posts(‘cat=2’);
while (have_posts()) : the_post();

$contenth .=’

• <a href=”‘;

$contenth .='”>’;
$contenth .= the_post_thumbnail();
$contenth .= the_permalink();
$contenth .= ‘
‘;

endwhile;

$contenth .= ‘
</div>’;

return $contenth;

ob_end_flush();
}

but it is not working. Does anyone see anything wrong with this?