It all began in the year 1984 when James Cameron came up with the first 'Terminator' which became an action/sci-fi classic during that time. The 1984 classic depicted merciless machines trying to end mankind.
Genisys depicts Skynet as a fully evolved cyber organization which has its presence everywhere in its own created reality. It has the power to not only attack from the future but also has the capability to attack from the past. It can also attack the real world at will.
In this movie, the resistance has successfully managed to infiltrate the Skynet HQ and thereby capturing the time machine. However, Skynet managed to send a terminator (T-1000) back in time to kill Sarah Connor (Emilia). Little does Skynet know that another old not obsolete and powerful T-800 (Arnold) whom Sarah fondly calls 'Pops' will do anything to protect Sarah from getting killed from Skynet.
It is not fair to compare the chemistry of Courtney and Emilia to that of Linda Hamilton and Michael Biehn from the first two parts of the franchise series as they are at a completely different level altogether.
In this movie, we see Byung-hun Lee in place of Robert Patrick as the liquid metal T-1000. The special effects in this movie are quite amazing. This movie has kept the tradition alive with the "I'll be back" phrase being reinstated as part of Arnold's character. This movie is a must watch for all Arnold fans as he is definitely back with a kick-ass action packed performance.