Half-Life 2: Episode 3 DLC (Opposing Force 2)

Opposing Force 2 is an expansion pack of Half Life 2: Episode Three, it tells how adrian shepard survived and made his appearance in the game

Plot
After the events of opposing force, Adrian shephard is in a temporary sleep thanks to the feats of G-Man, He is awakened by himself that says his time has come again, Adrian wakes up in the middle of a forest where a group of soldiers is being attacked by a squadron of Combine, After helping them he learns of the seven o'clock war and the total annihilation of the armies of the earth and the redemption of the land for The Alien Race COMBINE, After setting up a camp the squadron learns by radio that a new portal opened in missisipi (Region where the game goes) And that the COMBINES were planning to bring a new species of weapon that could destroy cities and annihilate the human race

Shephard and his new offspring depart to try to close the portal and during the game's events go through various locations, including a COMBINE base that is totally cleared by the squadron. They finally manage to get to Jackson where the portal is open, but are attacked by surprise and the squad sacrifices itself so that shepard can proceed, After crossing the city he finally arrives at the site of the portal where he can close it using a device that he obtained earlier, He then escapes of the city and becomes a legend for the rebels, Eventually arrives at the place where later gordon freeman would find it in (Half Life Episode 3)

Trivia
The game tells how adrian shephard made his appearance in half life episode three https://ideas.wikia.com/wiki/Half-Life_2:_Episode_3