Breakdown of Мне трудно следить за сюжетом, если фильм слишком сложный.
Questions & Answers about Мне трудно следить за сюжетом, если фильм слишком сложный.
Because Russian uses a very common pattern here: dative + predicative word + infinitive.
So Мне трудно следить... literally works like For me, it is difficult to follow...
The person experiencing the feeling or difficulty goes in the dative case, which is why you get мне rather than я.
If you wanted to use я, you would need a different structure, for example: Я с трудом слежу за сюжетом.
Russian often does not use a dummy subject like English it in this kind of sentence.
English says: It is hard for me to follow the plot.
Russian simply says: Мне трудно следить за сюжетом.
This is called an impersonal construction. The sentence is complete without any subject like это.