The Wings of a Butterfly is a very cute and very fun Short Trip.  I love how it is written and narrated by Colin Baker.  He does a great job at selling his own material.  It is a very pleasant listen overall.  The story is silly, in that a pair of pants being made incorrectly leads to the end of a certain civilization, but that silliness works with the nature of this story.  It's all about the unintended consequences of time travel - a fun topic for this type of storytelling I'm glad is being explored here.  It's a great Short Trip even if there isn't a ton of substance to it.  Any Classic Who fan would enjoy the listen.