Red burst
The red bursts were a series of temporal anomalies first detected by Starfleet and the Klingons in 2257. Unlike anything Starfleet had encountered before, their precise synchronization all but ruled out natural phenomena being the cause. () Ultimately, all signals bar one turned out to have been set by Michael Burnham, the second Red Angel, directing the  to a wormhole that led her 930 years in the future to prevent Control from destroying all life in the universe. ()

Overview
The first appearance of the bursts occurred in perfect synchronization over a span of 24 hours in 2257. They were scattered across thirty thousand light years of the Milky Way Galaxy and would have required energy beyond Starfleet's understanding to produce. ()

The Klingons also detected the bursts, and had no explanation for them. High Chancellor L'Rell confirmed to Ambassador Sarek that they were not responsible. Kol-Sha interpreted them as an ill omen for L'Rell's rule: "seven drops of blood" ready to rain down on the Klingon people. ()

Spock had foreknowledge of the red bursts, which he first saw as a child. This prompted him to take a leave of absence from the . Before his departure, he left encrypted data about the bursts in his final personal log entry, in case he did not return. ()

The investigation
The initial set of seven signals appearing in perfect synchronization were picked up by Federation sensors but disappeared again after just enough time to get a reading, with the exception of one signal.

The remaining signal eventually stabilized long enough to get a fix on its position, at which point the Enterprise, captained by Christopher Pike, set out to reach it. Before anything else could be done, the Enterprise experienced a massive systems failure – later blamed by Pike on the holo-communications system. ()

As a result, Pike transferred his command over to the  in order to continue the mission. ()

Shortly after the bursts were detected, the Vulcan High Command directed Sarek to work with Starfleet in assembling a Federation task force. He went on to serve on this task force. ()

Signal 01: Interstellar asteroid

At the source of the burst, Discovery found an interstellar asteroid which contained the crash landed remains of the . While attempting to investigate the signal, a landing party consisting of Pike, Burnham, Evan Connolly, and Nhan discovered survivors aboard the Hiawatha including Jett Reno. Despite an encounter with the red angel, the crew was unable to determine who or what generated the signal. ()

After Discovery departed the region, Starfleet sent a team to investigate the area further. They found evidence of tachyon radiation, suggesting time travel was involved. ()

Signal 02: Terralysium

Sometime after the initial series of bursts, a second signal was detected. The transmission was too faint to determine the exact coordinates using regular means but was eventually pinpointed to a distant region of the Beta Quadrant. The signal was 51,450 light years away from the location of the ship. Using its spore drive, Discovery was able to reach the location of this new burst, the planet of Terralysium, immediately. Once there, Discovery found a previously unknown settlement of Humans. They were descendants of people saved from World War III by a mysterious entity.

Shortly after arrival, Discovery prevented radioactive debris from wiping out the planet's inhabitants. The burst was also visible from the planet's surface. ()

Signal 03: Kaminar

Discovery detected a third burst in orbit of Kaminar, the homeworld of the Kelpien species, which included first officer Commander Saru. As had been the case on Terralysium, the burst had been visible from the surface; Siranna, Saru's sister and priest of their village, referred to it as a "fiery sign". ()

While in orbit above Kaminar measuring the residual radiation from the burst, Discovery discovered an anomaly. While investigating the anomaly in Shuttle 5,  and Christopher Pike were attacked by an upgraded version of a probe they'd previously launched. ()

Essof IV

Discovery and NCIA-93 journeyed to Essof IV to attempt to capture the Red Angel. A landing party consisting of  Hugh Culber, Paul Stamets, , Spock, and Michael Burnham beamed down to the surface. While the team worked on the surface, on board NCIA-93,  and Leland worked to close the wormhole to prevent the Angel from leaving.

After enacting their plan to attract the Red Angel, which involved exposing Burnham to the toxic atmosphere of the planet, they waited for the Angel to arrive. The plan worked, and a burst soon appeared in orbit of the planet. The Angel arrived on the surface and revived Burnham; after which she was captured and revealed to be Burnham's mother. ()

Holding Gabrielle Burnham and the Red Angel suit on Essof IV caused gravitational distortions. Shortly after the Red Angel was captured, Leland's body was taken over by Control. While pretending to be Leland, Control ordered Georgiou and Tyler to steal the 's data archive from Discovery. Eventually, Georgiou realized Leland wasn't who he seemed, and she stopped the upload, leading to an altercation on the surface.

Once Burnham's mother was pulled back to the 33rd century, Burnham was beamed up to the Discovery along with Nhan, Paul Stamets and . A barrage of photon torpedoes destroyed the base but "Leland" survived. ()

Signal 04: Boreth

A burst, the fourth of seven, soon appeared over the Klingon planet of Boreth. Discovery used the spore drive to jump to the planet to investigate. While there, Pike went to the monastery to retrieve a time crystal. In the process, he was given a traumatic vision of his future. ()

Signal 05: Xahea

A fifth burst appeared when Captain Pike was unable to destroy Discovery and thus the 's data. The signal brought Discovery and Enterprise to Xahea, the homeworld of Her Serene Highness Me Hani Ika Hali Ka Po. Ensign Tilly, who had previously and secretly met Queen Po, deduced that her friend's engineering genius, evidenced by her ability to recrystallize dilithium, might be the reason for the signal. Queen Po devised a method of charging the time crystal so it could power a new time travel suit. ()

Signal 06: Wormhole
The sixth red signal appeared during the Battle near Xahea, the first to appear after Burnham realized she had set the previous signals, intended to guide the Discovery to 3188. Guided by the signal, Discovery successfully went through the wormhole. ()

Signal 07: Final signal

After discovering that Spock would not be able to join the Discovery in their journey to the future due to damage to his shuttle and his unwillingness to risk further damage to Discovery, Burnham promised to send a final signal to confirm the crew's safe arrival in 3188. This manifested near Terralysium four months after the Battle near Xahea, detected by the Enterprise orbiting Earth. After sending the signal, the Red Angel suit self-destructed as per Burnham's orders. ()

Summary of red bursts 

Communication