(covers information from an alternate timeline)
In an alternate version of the year 2390 she and Chakotay were romantically involved. She became very interested in the exploits of the USS Voyager and its crew, and helped Chakotay and Harry Kim search for the vessel after it disappeared while attempting to use a quantum slipstream drive in 2375.
She spent several years working with the former Voyager officers, trying to ascertain why the slipstream did not work and later, devising a plan to prevent the ship's loss. Tessa became quite close to Chakotay and began a romantic (and sexual) relationship with him sometime prior to 2390. Both Chakotay and Harry told her many stories about the Voyager crew, including The Doctor.
In 2390, Tessa participated in a plan devised by the group to use a Borg interplexing beacon to send a message to Seven of Nine back in 2375 and hopefully avert the disaster which caused the destruction of the ship. It was not sanctioned by Starfleet, and in violation of the Temporal Prime Directive. The group had to steal the interplexing beacon, and Tessa also assisted Chakotay and Harry in the theft of the Delta Flyer from a Federation shipyard, accompanying them to an ice planet where Voyager's wreckage had become entombed. After the Doctor's program and Seven's corpse had been retrieved, Tessa went to Voyager along with Chakotay in order to download sensor logs needed for the transmission. Although Chakotay was hesitant to carry out the plan, which would effectively rewrite history and prevent him from ever meeting Tessa, she reminded him of how important it was they succeed.
Just a few hours later, the Flyer was intercepted by the USS Challenger and ordered to stand down. Tessa and Chakotay were able to break the Flyer free of the Challenger's tractor beam, but not before destabilizing the warp core and creating a containment breach. Chakotay offered to transport Tessa to the Challenger, but she refused, wanting to stay with him until the last minute. Tessa was killed when the Flyer exploded, but Harry was able to transmit his message to Voyager with instructions to collapse the slipstream, saving the ship and erasing all events which had followed Voyager's slipstream flight. (VOY: "Timeless")