Cross, a skeleton veteran of the Royal Guard, meets various characters from the Undertale universe, including Sans, Papyrus, Undyne, Alphys, and Toriel. They discuss Cross's past and his connections to the Multiverse. However, their conversation is cut short as Cross receives a message from Ink, who informs him that the Multiverse has been destroyed.
Cross and Ink meet, and Ink explains that XGaster is responsible for the destruction of the Multiverse. Cross is skeptical, but Ink convinces him to work together to stop XGaster. They are ambushed by a "Fatal Error" entity, which is a version of Geno from a different timeline.
During the fight, XGaster appears and saves Cross by restoring his body. Ink is left to deal with the aftermath, and he meets with Core!Frisk and Dream, who explain that the timeline is disconnecting from the Multiverse. Ink decides to take action and finds Sans, asking for his help.
The story ends with Sans reflecting on the events that have transpired, and Geno wondering if the happy ending they have achieved is truly the best outcome. The story concludes with a lyrical sequence, where the themes of freedom, survival, and the search for a proper way to come alive are explored.
Here are the key facts extracted from the text:
1. Cross, a skeleton, is talking to Geno, Sans, and other characters.
2. Cross mentions that he has seen reality's darkest side and has scars that remind him of hope.
3. Geno says that the original universe and its timelines are the only ones left.
4. Ink, a character, appears and Cross asks him what happened before XGaster separated him from Chara.
5. Ink tells Cross that the Multiverse is gone.
6. Cross realizes that the Multiverse's destruction was true and that this place still exists as an original universe timeline.
7. Ink says that those who have seen reality's darkest side are linked.
8. Geno appears and tells Cross that he is not going to be wiped out by the X-Event.
9. Geno warns Cross that there is great trouble ahead for him and that he needs to find a way to break free from his isolation.
10. Fatal_Error, a character, appears and starts attacking Cross and Ink.
11. XGaster appears and saves Cross from Fatal_Error.
12. XGaster tells Ink not to do anything stupid.
13. Fatal_Error tries to take control of Cross's code.
14. Cross gives Fatal_Error his weapon, but Fatal_Error copies it and uses it against Cross.
15. Ink tries to help Cross, but Fatal_Error's attacks are too strong.
16. Core_Frisk and Dream appear and tell Ink that they cannot join the battlefield physically.
17. They explain that the timeline disconnects from the Multiverse, and no one can enter or leave this reality.
18. Ink decides to change the course of events and thanks Core_Frisk and Dream for the idea.
19. Sans appears, and Ink asks him for one last favor.
20. Ink and Sans part ways, and Ink promises that this will be the last time they see each other.
21. The scene ends with a song and lyrics about being free and not broken.
Note: Some facts may be implied or open to interpretation, but I have tried to stick to the most objective and verifiable information.