Dash overhears Dr. Holtz excitedly tell someone on a phone that he has made the most important discovery in all of human history.

Dr. Holtz is found dead on the lunar surface after making an unauthorized solo trip through the base airlock.

Dash tells his parents he does not believe Dr. Holtz's death was an accident and suspects murder.

Moon Base Commander Nina Stack tells Dash she will not investigate Dr. Holtz's death because there is no evidence of foul play.

Security worker Zan Perfonic secretly enlists Dash to covertly investigate what really happened to Dr. Holtz.

Kira Howard, having overheard Dash and Zan's conversation, convinces Dash to let her join the murder investigation.

Kira shows Dash security footage of Dr. Holtz's final moments, in which Holtz appears upset and secretly signs a hidden message.

The computer translates Dr. Holtz's sign language as a message saying he is being murdered and to find his phone.

Daphne confesses to corporate spying and reveals that a robot was secretly sent to the solar array on the night of the murder.

Dash and Kira secretly suit up and exit the airlock onto the lunar surface to find Dr. Holtz's hidden phone.

A remote-controlled robotic arm attacks Dash and Kira on the lunar surface, knocking Dash down and cracking his helmet.

Dash outsmarts the arm operator by lying about his location and makes it back inside with the phone before his helmet shatters.

Audio recovered from Dr. Holtz's broken phone reveals he discovered alien life and was threatened with his daughter's death to stay silent.

Garth Grisan is exposed as the murderer and placed under arrest by Nina after threatening to depressurize the entire moon base.

Zan reveals herself to Dash as an alien thought-projection and asks him to serve as humanity's secret interspecies contact.

Dr. Holtz's suspicious death sets 12-year-old Dash Gibson on a covert murder investigation inside Moon Base Alpha. With the help of new arrival Kira Howard, Dash uncovers a hidden sign language message left by Dr. Holtz pointing to a phone buried on the lunar surface. The two children risk their lives venturing outside the airlock, where a remote-controlled robotic arm nearly kills them. After recovering Dr. Holtz's damaged phone, the group hears a recording that exposes a deadly secret about alien life. Maintenance worker Garth Grisan is unmasked as the murderer and arrested by Commander Nina Stack. In the final twist, Zan Perfonic reveals herself as an alien thought-projection and asks Dash to become humanity's secret interspecies contact.

The core events of the murder mystery and alien revelation.

Dash's parents receive an urgent communication and inform Dash that Dr. Holtz died in an accident on the lunar surface.

Dash rushes toward the airlock hoping to see Dr. Holtz's body but Nina physically redirects him back to his residence.

School is cancelled and all ComLinks are shut down so NASA can control communication about Dr. Holtz's death.

Roddy explains to Dash why NASA has powerful reasons to publicly cover up any suspicion surrounding Dr. Holtz's death.

Nina tells Dash there are no security cameras in the bathrooms, refusing to pursue the footage he requests.

Roddy informs Dash that security cameras exist in all bathrooms on the base, revealing that Nina deliberately lied to him.

Nina assigns Dash to welcome new arrival Kira Howard, and Dash gives her a tour of the moon base.

Dash finds Roddy being bullied by the Sjoberg siblings, who have stolen his hologoggles and are tossing them back and forth.

Using his knowledge of low gravity, Dash outmaneuvers the Sjobergs, retrieves Roddy's hologoggles, and causes the siblings to crash into each other.

At the communal fresh-food dinner, Roddy chokes on his burger and the dislodged chunk strikes Lars Sjoberg in the forehead.

Lars violently flips his family's dining table in a rage and demands to be put on the next rocket back to Earth.

Late at night, Chang defends Dr. Holtz's memory against Lars's insults and knocks Lars unconscious with a resistance band in self-defense.

Dash manipulates Dr. Marquez during a therapy session into naming Sonja Sjoberg and Garth Grisan as people worth suspecting.

Kira, Dash, and Roddy notice Daphne is the only person absent from the mandatory memorial service for Dr. Holtz.

Chang repairs enough of Dr. Holtz's shattered phone for the group to hear the recording of the killer threatening Dr. Holtz.

Before the investigation gains momentum, Dash struggles to get adults to take his murder theory seriously, including Commander Nina Stack, who lies to him about the base's security cameras. The arrival of a new rocket brings Kira Howard, a fresh food delivery, and a growing list of suspects for Dash to research, including the volatile tourist Lars Sjoberg. A violent outburst at the communal dinner and a late-night gym confrontation further expose Lars and Chang Hi-Tech as persons of interest. A cleverly manipulated therapy session with Dr. Marquez yields two crucial new suspects, including Garth Grisan. The discovery that Daphne is absent from Dr. Holtz's mandatory memorial leads Dash and his friends to confront her about suspicious behavior. Chang's repair of Dr. Holtz's broken phone ultimately provides the group with the breakthrough evidence needed to close in on the killer.

Supporting events that build the suspects and advance the investigation.

Dash's father explains the history between Chang and Dr. Holtz at dinner, describing their old dispute over stolen research credit.

Dash spots Chang Hi-Tech glaring at Dr. Holtz in an old news video, adding Chang to his list of suspects.

Dash realizes Dr. Holtz's late-night call had no audio lag, proving that Holtz was speaking to someone else on the base.

Dash receives a threatening text warning him to stop investigating or he will end up like Dr. Holtz.

Dash's parents attribute the threatening text to the Sjoberg siblings and dismiss it as cruel but harmless.

Dash discovers Daphne behaving suspiciously at a base computer late at night instead of monitoring the robot she oversees.

Dash updates Zan on the sign language discovery and his latest suspects during a private meeting in his family's residence.

Kira convinces Dash they should go onto the lunar surface that very night rather than waiting for more help from Zan.

Dash tries repeatedly to speak with Zan before the moonwalk but she subtly warns him away each time they are in public.

Kira and Dash experience euphoria bounding across the untouched lunar surface together on their way toward the solar array.

Covered in moon dust after being knocked down, Dash stays completely still to hide from the robotic arm's camera feed.

Kira's father publicly shouts that there is an undeniable killer on board, throwing all residents of the base into panic.

The computer misinterprets Chang's repair request in a way that suddenly reveals to Dash the identity of Dr. Holtz's killer.

Dash's mother re-examines the sign language footage and confirms the message spells out the name Garth, not the word Earth.

Dash agrees to be Zan's secret contact for humanity and asks her to teach him how to travel through space by thought.

Dash's investigation becomes personal when he receives a threatening text warning him to stop asking questions, but adult dismissal of the threat only deepens his resolve. Key discoveries pile up, including the realization that Dr. Holtz spoke to someone on the base that night and an old rivalry between Chang and Dr. Holtz captured in news footage. Kira pushes Dash to take a bold risk by going onto the lunar surface after dark, an exhilarating but dangerous choice that nearly costs Dash his life when he is attacked and left with a cracked helmet. After the attack, revelations arrive in rapid succession: the group hears the damning audio recording, the computer makes a telling misinterpretation, and Dash's mother confirms the killer's name is spelled out in Dr. Holtz's final sign language message. The story closes with Garth's exposure and arrest, followed by Dash's private discovery that Zan Perfonic is an alien presence who has chosen him as humanity's first interspecies contact.