syuuden ni maniaeba, konya ha ie ni kaereru.

終電 means the last train of the day.

• 終 = end, last
• 電 here comes from 電車, meaning train

So 終電 is the final train you can catch that night. It is a very common word in everyday Japanese, especially when talking about getting home late.

In 終電に間に合えば, the particle に marks the thing you are making it in time for.

So:

• 終電に間に合う = to make it in time for the last train

This に is not marking a destination here. It is tied to the verb 間に合う, which often takes に to show the deadline, event, or target that you are in time for.

Examples:

• 電車に間に合う = make it in time for the train
• 授業に間に合う = make it in time for class
• 締め切りに間に合う = make it in time for the deadline

間に合えば is the -eba conditional form of 間に合う.

• dictionary form: 間に合う = to be in time, to make it in time
• conditional: 間に合えば = if one makes it in time / if I make it in time

How it is formed:

• 間に合う is a u-verb
• change the final う to え and add ば
• 間に合う → 間に合えば

So the first part means:

• 終電に間に合えば = if I make it in time for the last train

Yes, in natural English this sentence is usually understood as I:

• If I make the last train, I can go home tonight.

Japanese often leaves out the subject when it is obvious from context. There is no explicit 私が here, but the speaker is almost certainly talking about themself.

So both parts are understood with the same subject:

• (I) make it in time for the last train
• (I) can go home tonight

The は after 今夜 marks tonight as the topic or as a contrastive time frame.

So 今夜は gives a nuance like:

• as for tonight
• at least tonight
• tonight, ...

In this sentence, it helps frame the result:

• If I make the last train, tonight I can go home.

It can also subtly imply contrast with some other possibility, such as:

• maybe otherwise I would have to stay somewhere else
• maybe other nights are different

Japanese often uses は with time expressions to set the scene or emphasize that time period.

They are doing two different jobs:

1. 終電に間に合えば

   • に marks the thing you must be in time for
   • for the last train

2. 家に帰れる

   • に marks the destination
   • to home

So even though the particle is the same, its role depends on the verb it is used with.

帰れる is the potential form of 帰る.

• 帰る = to go home / return home
• 帰れる = can go home / be able to go home

So the sentence is not just saying I will go home tonight. It is saying I will be able to go home tonight, depending on whether the condition is met.

That matches the logic of the sentence:

• if I catch the last train, then I can get home

帰る is a u-verb, so its potential form is made like this:

• 帰る → 帰れる

More generally for many u-verbs:

• change the final u sound to the corresponding e sound
• then add る

Examples:

• 行く → 行ける = can go
• 飲む → 飲める = can drink
• 帰る → 帰れる = can return/go home

So 家に帰れる means can go home.

The -eba form often sounds like a straightforward condition: if X happens, then Y.

Here:

• 終電に間に合えば、今夜は家に帰れる。
• If I make it in time for the last train, I can go home tonight.

The speaker is presenting a condition and its result in a fairly neutral, logical way.

Compared with other conditionals:

• 間に合ったら can sound a little more like if/when I manage to make it
• 間に合うと would sound more general or automatic, and is less natural here
• 間に合えば fits well for a practical condition

Yes, 家へ帰れる is also possible.

Both に and へ can mark direction with movement verbs, but there is a slight difference:

• に focuses more on the destination
• へ focuses more on the direction toward it

With 帰る, both are common:

• 家に帰る
• 家へ帰る

In this sentence, 家に帰れる sounds very natural and standard.

Here, 家 is best understood as home.

Although 家 can literally mean house, in expressions like:

• 家に帰る
• 家にいる

it often means home, not just the physical building.

So 家に帰れる is naturally translated as:

• can go home rather than
• can return to the house

Yes, that is a strong implication.

The sentence explicitly says:

• If I make the last train, I can go home tonight.

This naturally suggests the opposite possibility:

• if I do not make the last train, I probably cannot go home tonight

That implication is very common in Japanese conditionals. The speaker does not state the negative outcome directly, but it is easy to infer from context.