Sonic Forces: Stress Test is the second issue in the Sonic Forces digital comic series.
On Angel Island, Knuckles the Echidna is resting next to the Master Emerald, enjoying the peace and quiet and thinking about how it has been a while since the last time he was made a part of one of Sonic the Hedgehog's adventures. Said thoughts are interrupted when Silver the Hedgehog calls his name, floating onto the island and attempting to warn him about "big trouble" of some sort involving Dr. Eggman. Knuckles, remembering Silver went back to the future previously, is convinced he is just dreaming, but Silver insists he has returned with dire news from the future. However, the two soon notice that the island around them has suddenly disappeared, and in its place is Pachacamac's village from the past, filled with Knuckles Clan members. Knuckles grabs and shakes Silver, asking him if he brought them back in time, but Silver tells him that he just returned to the present and is completely clueless.
In the midst of another attempt to inform him of the bad news, Silver notices something rise from the Master Emerald behind Knuckles and warns him of it. Knuckles is not worried, telling him that it is just Chaos, the peaceful guardian of the Chao, and that he is harmless. Much to the contrary, Chaos punches Knuckles, who mentions that he forgot the guardian has a bad temper and that he knows how to pacify him. Knuckles attempts to retaliate against Chaos, but fails to land an effective blow against the liquid creature, who simply blasts him away with a jet of water. Silver opts to defeat Chaos instead, using his telekinetic abilities to hold him in place. However, a small puddle of Chaos he failed to grab hits him, breaking his hold; after noting this as a "new trick", Knuckles tells Silver that they need to work together, ordering him to grant him an opening to punch Chaos's brain. Upon Knuckles's command, Silver once again uses telekinesis to grab Chaos, granting the echidna the opening he needs. Once Knuckles's punch connects, Chaos suddenly disappears in a flash of pink sparkles, as does Pachacamac's village, leaving Knuckles bewildered.
Silver is certain that all of this has something to do with the impending disaster; he explains further that something happens at this point in time that ruins the world, but the historical records on this event are either not written in detail or do not make sense, so he returned to the present to stop it in its tracks and save the future. Knuckles figures that Silver came to him because he would not have known about the events below until they had already come to pass and comes to the conclusion that his involvement in said events must be important to the world's salvation, so he vows to be very involved and lead the resistance against whatever is happening. Silver, while not certain that is necessary, is grateful for his help, and the two leap off Angel Island to act further. Unbeknownst to either of them, Dr. Eggman has been watching from above in his Egg Mobile with the Phantom Ruby in his grasp and is laughing evilly. The evil scientist is pleased that his first test of the Ruby's power was a success, believing he will not even need to steal the Master Emerald with it in his possession. He also proclaims that Sonic has no chance of survival against the Ruby's power.
- Chao (Mentioned)
- Dr. Eggman
- Knuckles Clan
- Silver the Hedgehog
- Sonic the Hedgehog (Mentioned)
- A sketch of the front cover for this issue was hidden in the PDF files for Sonic Forces: Moment of Truth.