In 1942, the prototype battleship, the HMS Defiance, went mysteriously missing without a trace. It is now 2018 and the HMS Defiance has been located and an expedition cruiser sent. You are a member of the cruiser's diving team and have been picked to go down to the cruiser to search the ship and bring back artifacts for study. However, when you are down there, you will trigger mayhem. Most of the mod takes place in the cruiser and you are one of few survivors as most of the crew have either evacuated or been killed. There are few weapons on board the cruiser, so you will not have a massive amount of weapons. The mod will be quite short but it should be enjoyable none the less.
HMS Defiance 1 & 2 video review: Youtube.com
HMS Defiance is average at best. It isn't that good of a mod but it's not terribly bad. The mod feels very amateur so go easy on this one, understand that this was the mod developer's earliest mod so there really isn't much to see.
It's short, but atleast there is something of a story within it. Go in and don't expect anything fancy, just play through and appreciate that the developer will try bigger and better things in the future.