User blog comment:Plaguenumber3/Guard colab returns/@comment-24479473-20140521063728/@comment-23200172-20140522185624

I have it!!! It may not work with cannon but oh well.

A  ship (damaged) which crashes on the world is carrying gene-seeds from a failed SM combat mission. It was split off the fleet of ships because they fell under attack by the Dark Eldar raiders. It took a round from the Zoragon planetary defense which breaks up in atmosphere and as a result the Star Tigers are sent to recover said gene-seed but fail and due to the fact lots of gene-seeds are left and an xeno race has it SM company/companies has failed the Imperium decides to go overkill on the Zoragon.