The mother finds out from a police officer at her door that her son—who historically has suffered from drug problems—was killed in a car accident alongside his girlfriend. However, the police officer also informs her that they left behind a baby boy, which would be her grandson. Later, the girlfriend’s mother confirms that the two indeed left a child.

The mother meets with a social worker, who introduces the mother to her grandson. The grandson plays with Legos, but when the mother tries to play with him, he ignores and pulls away from her. The social worker says to just let him be and follow his lead, after which he says that the mother will be granted temporary custody for a few months until a fitting family is able to adopt.

In her kitchen, the mother watches her grandson play with Legos again. She tries to get through to him, but he remains cold. She shows him the bed where he’ll be sleeping, after which she bathes him while he plays with Legos in the bathroom. She thinks about how her son and his girlfriend were living in their car. Later at night, the grandson sleeps with his Legos in his hands. In the morning, he eats cereal and builds his Lego tower as usual. His ritual doesn’t change through the mornings. He only communicates with clicks, buzzes, and grunts.

One day, the mother pulls out a box of old things and shows her grandson pictures of his father and his toy truck. The mother recalls her own son, what it was like to raise him. As a kid, the son is sometimes violent and has a low temper, much unlike the calmer grandson. She recalls the toy truck in particular, how it was an important birthday gift to her son. Toward his tantrums, the mother tried to use the toy truck in order to reinforce good behaviors and quell bad ones, but it didn’t really work. One day, the son tosses the toy truck out of the window, injuring a neighbor.

For lunch, the grandson eats hotdogs. The mother wonders about his silence, whether it was inherited or a result from trauma. The social worker, in a meeting, says that he doesn’t know exactly what happened to him in his previous household, that it could either be abuse or some condition. The mother concedes that it must have been drugs, as both her son and his girlfriend were drug addicts and only ever showed up at her house while high.

The mother tries to read to her grandson with the same books she read to her son. She thinks about how it’s sometimes easier to raise him than how it was to raise her son, as he’s much calmer and less violent. By summer, she enrolls him in preschool with special education teachers. However, he remains uncooperative with them, as well as a speech therapist who visits the mother’s house. Together, the speech therapist and mother struggle to get through to him or get him to speak.

After two months, the social worker calls the mother and tells her that her temporary custody is over, as two parents have stepped up to permanently foster the grandson. The mother slightly protests, to which the social worker tells her that she can file for an extension, though he mentions her own admitted unfitness to parent him. The social worker then puts up an ultimatum: there may not be any more fitting parents in the future willing to take him as he gets older. He also questions whether she, in her old age, can handle him as he gets bigger and stronger. Until tomorrow morning, the mother contemplates whether to let him go or let him stay.

The next morning, the mother puts up with another one of her grandson’s tantrums. She realizes that she can’t be the right parent for him. By noon, the social worker arrives and takes him away. She naps through the day, reminiscing on that last moment with him. Before he leaves her house, he looks outside, sees a cab, and calls out the color yellow.