Ellie receives this pistol from Joel at the end of the plaza battle in Pittsburgh, despite his prior reluctance to allow Ellie to carry a firearm. As with Tess and other NPCs, Ellie's pistol has infinite ammunition. It is seen in action only if she is in trouble, as Joel says "It's for emergencies only" when Ellie first receives the pistol off of Joel, most notably in the battle with Hunters and Infected at the climax of the Pittsburgh chapter.
She uses the gun throughout the rest of the Summer chapter and even uses it to kill infected which save her and Henry's life. She states that Joel would be proud of her. She uses it also when she and Joel reach the University of Eastern Colorado. It is likely that it was recovered with her own backpack by Joel, or she could have found another model.
The player has control over this weapon during the chapter Lakeside during the Winter segment of the main game, where it functions near-identically to Joel's 9mm Pistol. While the player is controlling Ellie, her pistol can run out of ammo. She continued to use it during the Spring segment. It can be found in multiple Safes and behind many Shiv Doors as 50 usable parts.
Ellie uses her pistol to defend herself against a group of Cannibals in the mall in Colorado while seeking medical supplies for Joel, who had been wounded during their previous encounter at the University.
It is modeled to resemble a Beretta 70-series lightweight pistol. It is sometimes identified as a model-71 Jaguar. In real life, this weapon is chambered in .32 ACP, .380 ACP or .22LR calibers. However, in the game, it is a similar 9mm pistol with a different magazine capacity, higher recoil per-shot, and cosmetic differences as well. In the story however, it is not actually identified as either of those. If one zooms in on the slide in Photo Mode far enough, they can see the words, "Inkyo Brenny Carene VT Caliber .22LR."
During Left Behind, this semi-automatic pistol can also be seen in the hands of Riley, who in the cut scenes uses a normal 9mm pistol based on the Colt Defender, which all the other 9mm pistols besides Marlene and Ellie's are based on.
There is a glitch during the University Chapter that gives the player the ability to non-canonically kill Ellie with the newly-acquired Flamethrower. This will cause her to collapse and scream, and lie limp. This handgun will then have the possibility of being picked up Joel. Once the player picks it up, they only have enough time to fire it once before a respawn of Ellie, which resets the Beretta Model 70 back in her inventory. However, one can actually keep the semi-automatic pistol in conjunction to their own 9mm Pistol if they shoot Ellie with the Flamethrower in the Science Building, just as she is about to open the door to the top floor. This must be done carefully, and the Beretta Model 70 must be picked up at once. Although the firearm's texture often glitches and it is invisible in it's holster, it can still be kept for the rest of the game, albeit unupgradeable.