The entire series 1 is encompassed by the Rift story arc.
The rift is mentioned/seen in many episodes of series 1.
The Breaking Dawn
The Controller just before his defeat warns Morbius that "the Rift will open and Darkness will fall".
The Space Gangster
After the team teleports back to The Protector, an orange curtain of energy(similar to the Cardif rift) can be seen in the backgound
The Rutan prophecy: "We have seen it, the Darkness falling over creation. The Dark Lord shall open the Rift and the evil ones shall come, and onlly the Light Guardian can stop it".
The Bodyswaper says that he only swaped bodies with Morbius because "[he] saw the darkness and the end of everything".
The Degradation of Time
Commander Cr'it of The Skaro Degradations says that he escaped the Time War via a rift in time, later in the episode he atempts to open it and rescue the rest of the Degradations.
A Dark Collective
Another Rift similar to the ones in The Space Gangster and The Degradation of Time is discovered by the team and later used against the Darksmiths. This is the first time Morbius wonders what's causing the Rifts to occur.
Old Times in New York
Jack's former partner James Ducard atempts to tap into the power of a space-time rift found on Earth.
The Rift Opens
Warned by the Cloister Bell, the Guardians discover a colosal Rift in the Solar Sistem.
To Be Added.
A recurring story arc beginning in series 1 and being carried into series 2.
The Might of The Daleks
Last words of the episode: Morbius mustn't recieve the chance for Redemption, he must be EXTERMINATED. - Dalek Supreme.
The Rift War
Ending narroation: We saved the universe from the darkness, but I had no concept of my greater role in events. The time will come, where the destiny of the Time Lords will be in my hands. The time will come, when I recieve my chance for Redemption. - Morbius.