Catches up just after the first one. This time the brother is judged. However this time the story part in hell is very limited, and most of the movie is lesser than the first one.

The guardians, again, bet they whole job that they will get him through reincarnation, which not only is not original but really cheapens the move in the first one. Also looks like the dead are judged quite harshly, but the guardians seem to break the law again and again without much consequences.

What happens in hell is almost meaningless, contrary to the first one he doesn't even have to face trials on his merit, they just need to prove that he has been unfairly killed.
There are two main storylines.
One is about Hewonmak and Deok Choon helping a household god taking care of a soon to be orphan. That's cute, there are some fun scenes in their actions on Earth, but the whole thing is basically unrelated to the movie's concept. It could be an inclusion of a discarded scenario from a totally different not so good comedy movie, there would be no difference.
The other is a series of flashbacks from the guardians' lives a thousand years ago. Again, that could have come from a totally unrelated historical drama (though compared to the other storyline, that would have been an ok one). Every twist is entirely predictable though, and everyone is related in every way possible.

Again the conclusion is an overdose of exaggerated good sentiments with everybody crying.

Though it comes out as a all's well that ends well and nice people win kind of story, the moral of it is highly questionable.
First is clear that rules are entirely optional, and won't apply to the ones the people in power are close to. Whether it be for people on earth, the dead, or even the guardian.
[spoiler]Gang Rim basically becomes a guardian because his father is the king of hell.
He decides not to kill an evil spirit like he should have.
He saves two people that should have died. Once because it will help him on a trial, once because he feels a connection to the man.
The whole earth storyline here is guardians intervening directly in mortal affairs, even beating people up.
They constantly get special treatment for their trials.
A guy literally dies because they bring him as witness (well, his trial should be quick if they just have to show he was killed unfairly).
There's an old guy that has already outlived his normal lifespan by years. They're supposed to bring him as part of their bet on the current trial. Yet they decide to give him two decades more because they just like him. And... no consequences on their mission. Where's the justice for the hundred of thousands other orphans ?
[/spoiler]

In retrospective it all looks more like nepotism, favoritism and corruption than justice and morals.

If you liked the first one, it's interesting to have a look at the guardian's past lives. Otherwise, on his own, this one is not particularly good.