Riddles ( episode ) Tuvok loses his memory along with his Vulcan emotional self - control when he is attacked by mysterious aliens . Summary . Teaser . Returning home to in the " Delta Flyer " , Neelix and Tuvok have been left in each other ' s company . While Tuvok tries to work quietly , Neelix tries to keep them both entertained , irritating the Vulcan ( although naturally he tries not to show it ) . Eventually , Tuvok agrees to try to answer a riddle set by Neelix which concerns an ensign who is able to survive while stranded on a planet for a year with no resources other than a calendar . However Tuvok is not amused when the answer turns out to be a simple play on words – the ensign survives by eating the " dates " from the calendar . Retreating to the aft section , Tuvok encounters a cloak ed alien intruder downloading files from the " Delta Flyer " s computer core . As he attempts to detect the cloaking frequency , Tuvok is subjected to a neuroleptic blast from the cloaked alien . Neelix hails " Voyager " and signals a mayday . Act One . Neelix and Tuvok are picked up by " Voyager " and Tuvok is taken to sickbay where he lies in a deep coma . Fortunately , The Doctor stabilizes him . Captain Janeway asks Neelix about what happened , but he was focused on getting the ship back , and instantly regretful that he didn ' t look for more evidence on the way back to the ship . She comforts him that he did his duty and saved Tuvok . With no other leads as to who may have attacked Tuvok , Janeway decides to ask the Kesat if they know anything . They send Naroq , an investigator who believes Tuvok was attacked by the Ba ' Neth , an extremely xenophobic species that are widely believed not to exist and often attempt to steal tactical data from passing species ( explaining why it was downloading files from the " Delta Flyer " ) . This , however , is his own theory , as his government considers this species a myth . He is very excited to combine his resources with " Voyager " ' s to prove his theory . Janeway agrees , and allows him to scan Tuvok , who is the only one out of the 13 incidents to have survived . Neelix lingers in sickbay and undertakes a campaign to help Tuvok recover , despite Tuvok ' s history of casual disregard for him . With his usual over - enthusiasm , he proceeds to gather many of Tuvok ' s personal effects from his quarters and place them around him . Further , he wants to re - enact " Clash on the Fire Plains " . The Doctor restrains him a little , as he is trying to work . While arguing , suddenly , they notice Tuvok has sat up and is alert . They start to explain what happened , but he doesn ' t respond . The Doctor scans him , but Tuvok seems concerned about it . Neelix has to demonstrate that it won ' t hurt before Tuvok will let The Doctor scan him . It appears he has lost his memory . Act Two . Later , Seven of Nine and Naroq find residual particles in the aft of the " Delta Flyer " . Using technology developed by Naroq , they illuminate a silhouette of the attacker . Janeway theorizes that the technology can be adapted to " Voyager " s sensor s to reveal the alien race ' s ships . Back in sickbay , The Doctor informs Janeway that Tuvok has regained consciousness but is a little disoriented . The Doctor explains that Tuvok has lost his memory as a result of the encounter with the alien on the shuttlecraft and that his brain is in the process of rebuilding itself – which may take time . Neelix decides to take Tuvok on a tour of the ship in hopes that it will jog his memory . Neelix and Tuvok go to the bridge where the severity of Tuvok ' s condition is revealed . Tuvok is dazed and incapable of vocalization or understanding his whereabouts . Neelix then takes Tuvok to his quarters . Back on the bridge , Janeway works with Seven as she works from astrometrics to integrate the scanning technique into the deflector array . When the changes come online , several alien ships are revealed in proximity to " Voyager " . The ships attack " Voyager " and retreat before " Voyager " can determine their cloaking frequency with its sensors . As Neelix is comforting Tuvok , he finally responds to him , calling him by name . Act Three . Tuvok begins to have rudimentary conversations with Neelix in his quarters . Tuvok ' s recent affliction shows a stark contrast with the past : he treats Neelix as his protector and friend . When Neelix and Tuvok go to Janeway ' s ready room to meet " Voyager " s alien colleague , Tuvok is unable to remember the needed frequency . Naroq pushes , but Janeway ends the questioning , as Tuvok is disturbed by the memory . Janeway offers to have a meal with Tuvok , but Tuvok states that he would prefer to stay with Neelix . Some of the crew attempt to spend some time with Tuvok to help him remember . Tuvok and Neelix go to the mess hall , where Harry Kim tries to re - acquaint Tuvok with " kal - toh " , but Tuvok , failing the contest , angrily states that he doesn ' t like the game any more . When they return to sickbay , Tuvok sees his personnel file and expresses his frustration with his lost former self and the talents lost with it . Tuvok has a violent outburst and The Doctor , seeing that Neelix ' s presence in sickbay is upsetting him , orders the Talaxian to leave . Act Four . As Neelix sits sadly in an empty mess hall , he is joined by Seven of Nine , who is still trying to decode the riddle of the cloaking frequency . Neelix has a riddle of his own : " " When is a Vulcan no longer a Vulcan ? " " . As the two talk , Seven tells Neelix that what Neelix has been doing is trying to get the old Tuvok back , when in fact what he should be doing is concentrate on the new individual that he has become . Neelix realizes what she is saying , and leaves reinvigorated . Later , Neelix and Tuvok meet in sickbay where they have a lengthy conversation about Tuvok ' s treatment of Neelix to date . Tuvok gives Neelix a flower he made of wax in order to make up for his angry outburst earlier in sickbay . Tuvok has a difficult time understanding why he and Neelix were not previously good friends . Neelix jokes about the sometime rigid seriousness of the " old Tuvok " and both have a good laugh . Tuvok decides that he is not interested in logic exercises , meditation and " kal - toh " , but would rather do something else . So Neelix takes him to the mess hall . There , Tom Paris and Harry Kim test the many delicious dishes , particularly desserts , that Tuvok has been working on . Janeway enters and joins in the testing . She also prompts Tuvok to try to recall the much - needed cloaking frequency again . Tuvok resists , but when he presents the cake he has been adding frosting to , Janeway notices that the pattern atop the cake is the missing frequency . Tuvok says that ' s what he saw . They eventually detect a large reading in one of a few systems . The deflector shield illuminates a large space station and ships . Act Five . Now that Janeway is equipped with the tactical information she needs , she is able to make contact with the alien species that attacked Tuvok . They negotiate to trade tactical information on " Voyager " s previous alien encounters for information on the weapon used on Tuvok . The aliens refuse but " Voyager " s alien colleague offers the equipment he used to break their cloak in exchange for the information . Both sides agree . Neelix goes to Tuvok ' s quarters to inform him that The Doctor has come up with a treatment for Tuvok ' s condition . Tuvok reacts poorly to this news and says that he would rather have fun with Neelix than return to his previous state . Neelix charmingly reveals his understanding of Tuvok . " " You won ' t call it fun . . . you ' ll call it ' deriving satisfaction . ' But it ' s basically the same thing . " " Tuvok affectionately tells Neelix that he has really enjoyed his company . Neelix shows appreciation and consoles Tuvok , but tells him that he thinks it best if Tuvok returned to his tactical officer position , where he is needed . After the procedure , Neelix runs into Tuvok in the mess hall , who is his usual cold , logical , distant self and , as expected , dodges Neelix ' s questions about how he is feeling . Neelix tells Tuvok that he is preparing a dinner in his honor and asks him if he would like to prepare one of his favorite desserts . Tuvok replies that he has much more important things to do than engage in the preparation of nutritionally - deficient foods . As a slightly despondent Neelix gets up to leave , Tuvok says that , after giving more thought to the riddle concerning the ensign stuck on the planet , he has concluded that the ensign could have also survived by eating the " sunda ( y ) es " . A much - amused Neelix notes that while the answer is clever , it isn ' t really very logical . Tuvok , who seems a bit surprised at himself , agrees with a very slight smile . Memorable quotes . " " The Vulcan brain – a puzzle wrapped inside an enigma housed inside a cranium . " " " " Don ' t worry , Captain . Tuvok will be back to his old self before you can say ' live long and prosper ' . " " " " You said I was supposed to stimulate his senses . " " " " I said stimulate them , Mr . Neelix , not annihilate them . " " " " I want to be able to have fun . . . with you ! " " " " . . . If I stay here and try to talk to Tuvok , I may be able to provoke some sort of response ? " " " " If anyone can provoke Tuvok , Mr . Neelix , it ' s you . " " " " The object of the game is to turn this jumble of rods into a perfect sphere . We take turns positioning our pieces . Whoever gets the shape to appear first , wins . " " " " I like the way it looks now . " " Links and references . References . 56 alpha ; advisor ; airponics bay ; Ba ' Neth ; Ba ' Neth outpost ; Ba ' Neth ship ; Borg Collective ; calendar ; champagne ; " " ; chocolate ; class L ; " Clash on the Fire Plains " ; cloaking device ; cloaking frequency ; cortical stimulator ; ; deflector array ; degree ; " Delta Flyer " ; direct cortical stimulation ; Federation ; fetran sauce ; flower ; Grid 216 ; hive mind ; hot spring ; holodeck ; incense ; isotope ; jazz ; Jiballian fudge cake ; " kal - toh " ; Kesat ; Kesat homeworld ; Kesat Security ; Kesatian ale ; logic ; Mister Vulcan ; multiped ; neuro - biology ; neuroleptic shock ; neurostatic pulse ; paranoia ; pastry chef ; peppermint coulis ; parra creme sauce ; photolitic converter ; photonic warhead ; pistachio cake ; proto - Vulcan ; riddle ; Riddle ensign ; Risa Water Recreation Park ; Species , Starship , or Anomaly ? ; Starfleet Academy ; sundae ; Sunday ; sweet leola root tart ; synaptizine ; tactical officer ; tactical database ; tactical station ; tea ; tentacle ; terra - nut souffle ; terawatt ; tractor emitter ; tricorder ; veridium ; Vulcan s ; wikki fruit sundae ; word play ; xenophobia